[v4] gdb/testsuite: add test for backtracing for threaded inferiors from a corefile
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Commit Message
This patch is based on an out-of-tree patch that fedora has been
carrying for a while. It tests if GDB is able to properly unwind a
threaded program in the following situations:
* regular threads
* in a signal handler
* in a signal handler executing on an alternate stack
And the final frame can either be in a syscall or in an infinite loop.
The test works by running the inferior until a crash to generate a
corefile, or until right before the crash. Then applies a backtrace to
all threads to see if any frame can't be identified, and the order of
the threads in GDB. Finally, it goes thread by thread and tries to
collect a large part of the backtrace, to confirm that everything is
being unwound correctly.
Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
Reviewed-By: Luis Machado <luis.machado@arm.com>
---
Changes for v4:
* Luis mentioned that my strategy for starting the inferior didn't work
with native-extended testing. Changed to use runto_main instead
* Improved comments in the exp file based on Andrew's comments
* Minor cleanups with regards to TCL usage
---
gdb/testsuite/gdb.threads/threadcrash.c | 443 ++++++++++++++++++++++
gdb/testsuite/gdb.threads/threadcrash.exp | 233 ++++++++++++
2 files changed, 676 insertions(+)
create mode 100644 gdb/testsuite/gdb.threads/threadcrash.c
create mode 100644 gdb/testsuite/gdb.threads/threadcrash.exp
Comments
Ping!
On 20/12/2023 10:40, Guinevere Larsen wrote:
> Ping!
>
> --
> Cheers,
> Guinevere Larsen
> She/Her/Hers
>
> On 04/12/2023 18:33, Guinevere Larsen wrote:
>> This patch is based on an out-of-tree patch that fedora has been
>> carrying for a while. It tests if GDB is able to properly unwind a
>> threaded program in the following situations:
>> * regular threads
>> * in a signal handler
>> * in a signal handler executing on an alternate stack
>>
>> And the final frame can either be in a syscall or in an infinite loop.
>>
>> The test works by running the inferior until a crash to generate a
>> corefile, or until right before the crash. Then applies a backtrace to
>> all threads to see if any frame can't be identified, and the order of
>> the threads in GDB. Finally, it goes thread by thread and tries to
>> collect a large part of the backtrace, to confirm that everything is
>> being unwound correctly.
>>
>> Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
>> Reviewed-By: Luis Machado <luis.machado@arm.com>
>>
>> ---
>>
>> Changes for v4:
>> * Luis mentioned that my strategy for starting the inferior didn't work
>> with native-extended testing. Changed to use runto_main instead
>> * Improved comments in the exp file based on Andrew's comments
>> * Minor cleanups with regards to TCL usage
>> ---
>> gdb/testsuite/gdb.threads/threadcrash.c | 443 ++++++++++++++++++++++
>> gdb/testsuite/gdb.threads/threadcrash.exp | 233 ++++++++++++
>> 2 files changed, 676 insertions(+)
>> create mode 100644 gdb/testsuite/gdb.threads/threadcrash.c
>> create mode 100644 gdb/testsuite/gdb.threads/threadcrash.exp
>>
>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.c
>> b/gdb/testsuite/gdb.threads/threadcrash.c
>> new file mode 100644
>> index 00000000000..e476ae7b07d
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.threads/threadcrash.c
>> @@ -0,0 +1,443 @@
>> +/* This testcase is part of GDB, the GNU debugger.
>> +
>> + Copyright 2023 Free Software Foundation, Inc.
>> +
>> + This program is free software; you can redistribute it and/or modify
>> + it under the terms of the GNU General Public License as published by
>> + the Free Software Foundation; either version 3 of the License, or
>> + (at your option) any later version.
>> +
>> + This program is distributed in the hope that it will be useful,
>> + but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + GNU General Public License for more details.
>> +
>> + You should have received a copy of the GNU General Public License
>> + along with this program. If not, see
>> <http://www.gnu.org/licenses/>. */
>> +
>> +#include <pthread.h>
>> +#include <assert.h>
>> +#include <stdlib.h>
>> +#include <signal.h>
>> +#include <unistd.h>
>> +
>> +/* The delay that the main thread gives once all the worker threads
>> have
>> + reached the barrier before the main thread enters the function on
>> which
>> + GDB will have placed a breakpoint. */
>> +
>> +#define MAIN_THREAD_DELAY 2
>> +
>> +/* The maximum time we allow this test program to run for before an
>> alarm
>> + signal is sent and everything will exit. */
>> +#define WATCHDOG_ALARM_TIME 600
>> +
>> +/* Aliases for the signals used within this script. Each signal
>> + corresponds to an action (from the FINAL_ACTION enum) that the
>> signal
>> + handler will perform. */
>> +
>> +#define SPIN_SIGNAL SIGUSR1
>> +#define SYSCALL_SIGNAL SIGUSR2
>> +
>> +/* Describe the final action that a thread should perform. */
>> +
>> +enum final_action
>> + {
>> + /* Thread should spin in an infinite loop. */
>> + SPIN = 0,
>> +
>> + /* Thread should block in a syscall. */
>> + SYSCALL,
>> +
>> + /* This is just a marker to allow for looping over the enum. */
>> + LAST_ACTION
>> + };
>> +
>> +/* Where should the thread perform this action? */
>> +
>> +enum exec_location
>> + {
>> + /* Just a normal thread, on a normal stack. */
>> + NORMAL = 0,
>> +
>> + /* In a signal handler, but use the normal stack. */
>> + SIGNAL_HANDLER,
>> +
>> + /* In a signal handler using an alternative stack. */
>> + SIGNAL_ALT_STACK,
>> +
>> + /* This is just a marker to allow for looping over the enum. */
>> + LAST_LOCACTION
>> + };
>> +
>> +/* A descriptor for a single thread job. We create a new thread for
>> each
>> + job_description. */
>> +
>> +struct job_description
>> +{
>> + /* What action should this thread perform. */
>> + enum final_action action;
>> +
>> + /* Where should the thread perform the action. */
>> + enum exec_location location;
>> +
>> + /* The actual thread handle, so we can join with the thread. */
>> + pthread_t thread;
>> +};
>> +
>> +/* A pthread barrier, used to (try) and synchronise the threads. */
>> +pthread_barrier_t global_barrier;
>> +
>> +/* Return a list of jobs, and place the length of the list in
>> *COUNT. */
>> +
>> +struct job_description *
>> +get_job_list (int *count)
>> +{
>> + /* The number of jobs. */
>> + int num = LAST_ACTION * LAST_LOCACTION;
>> +
>> + /* The uninitialised array of jobs. */
>> + struct job_description *list
>> + = malloc (num * sizeof (struct job_description));
>> + assert (list != NULL);
>> +
>> + /* Fill the array with all possible jobs. */
>> + for (int i = 0; i < (int) LAST_ACTION; ++i)
>> + for (int j = 0; j < (int) LAST_LOCACTION; ++j)
>> + {
>> + int idx = (i * LAST_LOCACTION) + j;
>> + list[idx].action = (enum final_action) i;
>> + list[idx].location = (enum exec_location) j;
>> + }
>> +
>> + /* Return the array of jobs. */
>> + *count = num;
>> + return list;
>> +}
>> +
>> +/* This function should never be called. If it is then an assertion
>> will
>> + trigger. */
>> +
>> +void
>> +assert_not_reached (void)
>> +{
>> + assert (0);
>> +}
>> +
>> +/* The function for a SPIN action. Just spins in a loop. The LOCATION
>> + argument exists so GDB can identify the expected context for this
>> + function. */
>> +
>> +void
>> +do_spin_task (enum exec_location location)
>> +{
>> + (void) location;
>> +
>> + /* Let everyone know that we're about to perform our action. */
>> + int res = pthread_barrier_wait (&global_barrier);
>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>> +
>> + while (1)
>> + {
>> + /* Nothing. */
>> + }
>> +}
>> +
>> +/* The function for a SYSCALL action. Just spins in a loop. The
>> LOCATION
>> + argument exists so GDB can identify the expected context for this
>> + function. */
>> +
>> +void
>> +do_syscall_task (enum exec_location location)
>> +{
>> + (void) location;
>> +
>> + /* Let everyone know that we're about to perform our action. */
>> + int res = pthread_barrier_wait (&global_barrier);
>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>> +
>> + sleep (600);
>> +}
>> +
>> +/* Return the required size for a sigaltstack. We start with a single
>> + page, but do check against the system defined minimums. We don't run
>> + much on the alternative stacks, so we don't need a huge one. */
>> +
>> +size_t
>> +get_stack_size (void)
>> +{
>> + size_t size = getpagesize (); /* Arbitrary starting size. */
>> + if (size < SIGSTKSZ)
>> + size = SIGSTKSZ;
>> + if (size < MINSIGSTKSZ)
>> + size = MINSIGSTKSZ;
>> + return size;
>> +}
>> +
>> +/* A descriptor for an alternative stack. */
>> +
>> +struct stack_descriptor
>> +{
>> + /* The base address of the alternative stack. This is the address
>> that
>> + must be freed to release the memory used by this stack. */
>> + void *base;
>> +
>> + /* The size of this alternative stack. Tracked just so we can
>> query this
>> + from GDB. */
>> + size_t size;
>> +};
>> +
>> +/* Install an alternative signal stack. Return a descriptor for the
>> newly
>> + allocated alternative stack. */
>> +
>> +struct stack_descriptor
>> +setup_alt_stack (void)
>> +{
>> + size_t stack_size = get_stack_size ();
>> +
>> + void *stack_area = malloc (stack_size);
>> +
>> + stack_t stk;
>> + stk.ss_sp = stack_area;
>> + stk.ss_flags = 0;
>> + stk.ss_size = stack_size;
>> +
>> + int res = sigaltstack (&stk, NULL);
>> + assert (res == 0);
>> +
>> + struct stack_descriptor desc;
>> + desc.base = stack_area;
>> + desc.size = stack_size;
>> +
>> + return desc;
>> +}
>> +
>> +/* Return true (non-zero) if we are currently on the alternative stack,
>> + otherwise, return false (zero). */
>> +
>> +int
>> +on_alt_stack_p (void)
>> +{
>> + stack_t stk;
>> + int res = sigaltstack (NULL, &stk);
>> + assert (res == 0);
>> +
>> + return (stk.ss_flags & SS_ONSTACK) != 0;
>> +}
>> +
>> +/* The signal handler function. All signals call here, so we use SIGNO
>> + (the signal that was delivered) to decide what action to
>> perform. This
>> + function might, or might not, have been called on an alternative
>> signal
>> + stack. */
>> +
>> +void
>> +signal_handler (int signo)
>> +{
>> + enum exec_location location
>> + = on_alt_stack_p () ? SIGNAL_ALT_STACK : SIGNAL_HANDLER;
>> +
>> + switch (signo)
>> + {
>> + case SPIN_SIGNAL:
>> + do_spin_task (location);
>> + break;
>> +
>> + case SYSCALL_SIGNAL:
>> + do_syscall_task (location);
>> + break;
>> +
>> + default:
>> + assert_not_reached ();
>> + }
>> +}
>> +
>> +/* The thread worker function. ARG is a job_description pointer which
>> + describes what this thread is expected to do. This function always
>> + returns a NULL pointer. */
>> +
>> +void *
>> +thread_function (void *arg)
>> +{
>> + struct job_description *job = (struct job_description *) arg;
>> + struct stack_descriptor desc = { NULL, 0 };
>> + int sa_flags = 0;
>> +
>> + switch (job->location)
>> + {
>> + case NORMAL:
>> + /* This thread performs the worker action on the current thread,
>> + select the correct worker function based on the requested
>> + action. */
>> + switch (job->action)
>> + {
>> + case SPIN:
>> + do_spin_task (NORMAL);
>> + break;
>> +
>> + case SYSCALL:
>> + do_syscall_task (NORMAL);
>> + break;
>> +
>> + default:
>> + assert_not_reached ();
>> + }
>> + break;
>> +
>> + case SIGNAL_ALT_STACK:
>> + /* This thread is to perform its action in a signal handler on
>> the
>> + alternative stack. Install the alternative stack now, and then
>> + fall through to the normal signal handler location code. */
>> + desc = setup_alt_stack ();
>> + assert (desc.base != NULL);
>> + assert (desc.size > 0);
>> + sa_flags = SA_ONSTACK;
>> +
>> + /* Fall through. */
>> + case SIGNAL_HANDLER:
>> + {
>> + /* This thread is to perform its action in a signal handler. We
>> + might have just installed an alternative signal stack. */
>> + int signo, res;
>> +
>> + /* Select the correct signal number so that the signal handler will
>> + perform the required action. */
>> + switch (job->action)
>> + {
>> + case SPIN:
>> + signo = SPIN_SIGNAL;
>> + break;
>> +
>> + case SYSCALL:
>> + signo = SYSCALL_SIGNAL;
>> + break;
>> +
>> + default:
>> + assert_not_reached ();
>> + }
>> +
>> + /* Now setup the signal handler. */
>> + struct sigaction sa;
>> + sa.sa_handler = signal_handler;
>> + sigfillset (&sa.sa_mask);
>> + sa.sa_flags = sa_flags;
>> + res = sigaction (signo, &sa, NULL);
>> + assert (res == 0);
>> +
>> + /* Send the signal to this thread. */
>> + res = pthread_kill (job->thread, signo);
>> + assert (res == 0);
>> + }
>> + break;
>> +
>> + default:
>> + assert_not_reached ();
>> + };
>> +
>> + /* Free the alt-stack if we allocated one, if not DESC.BASE will be
>> + NULL so this call is fine. */
>> + free (desc.base);
>> +
>> + /* Thread complete. */
>> + return NULL;
>> +}
>> +
>> +void
>> +start_job (struct job_description *job)
>> +{
>> + int res;
>> +
>> + res = pthread_create (&job->thread, NULL, thread_function, job);
>> + assert (res == 0);
>> +}
>> +
>> +/* Join with the thread for JOB. This will block until the thread
>> for JOB
>> + has finished. */
>> +
>> +void
>> +finalise_job (struct job_description *job)
>> +{
>> + int res;
>> + void *retval;
>> +
>> + res = pthread_join (job->thread, &retval);
>> + assert (res == 0);
>> + assert (retval == NULL);
>> +}
>> +
>> +/* Function that GDB can place a breakpoint on. */
>> +
>> +void
>> +breakpt (void)
>> +{
>> + /* Nothing. */
>> +}
>> +
>> +/* Function that triggers a crash, if the user has setup their
>> environment
>> + correctly this will dump a core file, which GDB can then
>> examine. */
>> +
>> +void
>> +crash_function (void)
>> +{
>> + volatile int *p = 0;
>> + volatile int n = *p;
>> + (void) n;
>> +}
>> +
>> +/* Entry point. */
>> +
>> +int
>> +main ()
>> +{
>> + int job_count, res;
>> + struct job_description *jobs = get_job_list (&job_count);
>> +
>> + /* This test is going to park some threads inside infinite loops.
>> Just
>> + in case this program is left running, install an alarm that
>> will cause
>> + everything to exit. */
>> + alarm (WATCHDOG_ALARM_TIME);
>> +
>> + /* We want each worker thread (of which there are JOB_COUNT) plus the
>> + main thread (hence + 1) to wait at the barrier. */
>> + res = pthread_barrier_init (&global_barrier, NULL, job_count + 1);
>> + assert (res == 0);
>> +
>> + /* Start all the jobs. */
>> + for (int i = 0; i < job_count; ++i)
>> + start_job (&jobs[i]);
>> +
>> + /* Notify all the worker threads that we're waiting for them. */
>> + res = pthread_barrier_wait (&global_barrier);
>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>> +
>> + /* All we know at this point is that all the worker threads have
>> reached
>> + the barrier, which is just before they perform their action.
>> But we
>> + really want them to start their action.
>> +
>> + There's really no way we can be 100% certain that the worker
>> threads
>> + have started their action, all we can do is wait for a short
>> while and
>> + hope that the machine we're running on is not too slow. */
>> + sleep (MAIN_THREAD_DELAY);
>> +
>> + /* A function that GDB can place a breakpoint on. By the time we get
>> + here we are as sure as we can be that all of the worker threads
>> have
>> + started and are in their worker action (spinning, or syscall). */
>> + breakpt ();
>> +
>> + /* If GDB is not attached then this function will cause a crash,
>> which
>> + can be used to dump a core file, which GDB can then analyse. */
>> + crash_function ();
>> +
>> + /* Due to the crash we never expect to get here. Plus the worker
>> actions
>> + never terminate. But for completeness, here's where we join
>> with all
>> + the worker threads. */
>> + for (int i = 0; i < job_count; ++i)
>> + finalise_job (&jobs[i]);
>> +
>> + /* Cleanup the barrier. */
>> + res = pthread_barrier_destroy (&global_barrier);
>> + assert (res == 0);
>> +
>> + /* And clean up the jobs list. */
>> + free (jobs);
>> +
>> + return 0;
>> +}
>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.exp
>> b/gdb/testsuite/gdb.threads/threadcrash.exp
>> new file mode 100644
>> index 00000000000..996e020d1e8
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.threads/threadcrash.exp
>> @@ -0,0 +1,233 @@
>> +# This testcase is part of GDB, the GNU debugger.
>> +
>> +# Copyright 2023 Free Software Foundation, Inc.
>> +
>> +# This program is free software; you can redistribute it and/or modify
>> +# it under the terms of the GNU General Public License as published by
>> +# the Free Software Foundation; either version 3 of the License, or
>> +# (at your option) any later version.
>> +#
>> +# This program is distributed in the hope that it will be useful,
>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> +# GNU General Public License for more details.
>> +#
>> +# You should have received a copy of the GNU General Public License
>> +# along with this program. If not, see <http://www.gnu.org/licenses/>.
>> +
>> +# This test case looks at GDB's ability to get correct backtraces for a
>> +# crashed inferior, recreating it from a live inferior, a corefile and
>> +# a gcore.
>> +
>> +
>> +# Check that the inferior has 7 threads, and return the number of
>> threads (7).
>> +# We return the thread count so that, even if there is some error in
>> the test,
>> +# the final log doesn't get flooded with failures.
>> +
>> +proc test_thread_count {} {
>> + set thread_count 0
>> +
>> + gdb_test_multiple "info threads" "getting thread count" -lbl {
>> + -re "Thread" {
>> + incr thread_count
>> + exp_continue
>> + }
>> + -re "$::gdb_prompt " {
>> + gdb_assert {$thread_count == 7}
>> + }
>> + }
>> +
>> + return $thread_count
>> +}
>> +
>> +# Use 'thread apply all backtrace' to check if all expected threads
>> +# are present, and stopped in the expected locations. Set the global
>> +# TEST_LIST to be the a list of regexps expected to match all the
>> +# threads. We generate it now so that the list is in the order that
>> +# GDB sees the threads.
>> +
>> +proc thread_apply_all {} {
>> + global test_list
>> +
>> + set test_list { }
>> +
>> + set unwind_fail false
>> +
>> + gdb_test_multiple "thread apply all backtrace" \
>> + "Get thread information" -lbl {
>> + -re "#\[0-9\]+\\\?\\\?\[^\n\]*" {
>> + set unwind_fail true
>> + exp_continue
>> + }
>> + -re "\[^\n\]*syscall_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
>> + lappend test_list [multi_line ".*sleep.*" \
>> + ".*do_syscall_task
>> .location=SIGNAL_ALT_STACK.*" \
>> + ".*signal_handler.*" \
>> + ".*signal handler called.*" \
>> + ".*pthread_kill.*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*syscall_task .location=SIGNAL_HANDLER\[^\n\]*" {
>> + lappend test_list [multi_line ".*sleep.*" \
>> + ".*do_syscall_task
>> .location=SIGNAL_HANDLER.*" \
>> + ".*signal_handler.*" \
>> + ".*signal handler called.*" \
>> + ".*pthread_kill.*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*syscall_task .location=NORMAL\[^\n\]*" {
>> + lappend test_list [multi_line ".*sleep.*" \
>> + ".*do_syscall_task .location=NORMAL.*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*spin_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
>> + lappend test_list [multi_line ".*do_spin_task
>> .location=SIGNAL_ALT_STACK.*" \
>> + ".*signal_handler.*" \
>> + ".*signal handler called.*" \
>> + ".*pthread_kill.*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*spin_task .location=SIGNAL_HANDLER\[^\n\]*" {
>> + lappend test_list [multi_line ".*do_spin_task
>> .location=SIGNAL_HANDLER.*" \
>> + ".*signal_handler.*" \
>> + ".*signal handler called.*" \
>> + ".*pthread_kill.*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*spin_task .location=NORMAL\[^\n\]*" {
>> + lappend test_list [multi_line ".*do_spin_task
>> .location=NORMAL..*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*main\[^\n\]*" {
>> + lappend test_list ".*main.*"
>> + exp_continue
>> + }
>> + -re "$::gdb_prompt " {
>> + pass $gdb_test_name
>> + }
>> + }
>> +
>> + gdb_assert {$unwind_fail == false}
>> +}
>> +
>> +# Perform all the tests we're interested in. They are:
>> +# * test if we have 7 threads
>> +# * Creating the list of backtraces for all threads seen
>> +# * testing if GDB recreated the full backtrace we expect for all
>> threads
>> +
>> +proc do_full_test {} {
>> + global test_list
>> + set thread_count [test_thread_count]
>> +
>> + thread_apply_all
>> +
>> + gdb_assert {$thread_count == [llength $test_list]}
>> +
>> + for {set i 0} {$i < $thread_count } {incr i} {
>> + set thread_num [expr [llength $test_list] - $i]
>> +
>> + gdb_test "thread apply $thread_num backtrace" [lindex $test_list
>> $i]
>> + }
>> +}
>> +
>> +# Do all preparation steps for running the corefile tests, then
>> +# call do_full_test to actually run the tests.
>> +
>> +proc_with_prefix test_live_inferior {} {
>> + gdb_test "handle SIGUSR1 nostop print pass" \
>> + ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>> + "setup SIGUSR1"
>> + gdb_test "handle SIGUSR2 nostop print pass" \
>> + ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>> + "setup SIGUSR2"
>> +
>> + if {![runto_main]} {
>> + return
>> + }
>> +
>> + gdb_breakpoint "breakpt"
>> + gdb_continue_to_breakpoint "running to breakpoint" ".*"
>> +
>> + do_full_test
>> +}
>> +
>> +# Do all preparation steps for running the corefile tests, then
>> +# call do_full_test to actually run the tests.
>> +
>> +proc_with_prefix test_corefile {} {
>> + set corefile [core_find $::binfile]
>> + if { $corefile == "" } {
>> + untested "couldn't generate corefile"
>> + return
>> + }
>> + set corefile [gdb_remote_download host $corefile]
>> +
>> + gdb_test "core-file $corefile" \
>> + "" \
>> + "loading_corefile" \
>> + "A program is being debugged already\\\. Kill it\\\? \\\(y
>> or n\\\) " \
>> + "y"
>> +
>> + do_full_test
>> +}
>> +
>> +# Do all preparation steps for running the gcore tests, then
>> +# call do_full_test to actually run the tests.
>> +
>> +proc_with_prefix test_gcore {} {
>> +
>> + clean_restart "$::binfile"
>> +
>> + gdb_test "handle SIGUSR1 nostop print pass" \
>> + ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>> + "setup SIGUSR1"
>> + gdb_test "handle SIGUSR2 nostop print pass" \
>> + ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>> + "setup SIGUSR2"
>> +
>> + if {![runto_main]} {
>> + return -1
>> + }
>> + gdb_test "continue" ".*Segmentation fault.*" "continue to crash"
>> +
>> + set gcore_name "${::binfile}.gcore"
>> + set gcore_supported [gdb_gcore_cmd "$gcore_name" "saving gcore"]
>> +
>> + if {!$gcore_supported} {
>> + unsupported "couldn't generate gcore file"
>> + return
>> + }
>> +
>> + set corefile [gdb_remote_download host $gcore_name]
>> +
>> + gdb_test "core-file $corefile" \
>> + "" \
>> + "loading_corefile" \
>> + "A program is being debugged already\\\. Kill it\\\? \\\(y
>> or n\\\) " \
>> + "y"
>> +
>> + do_full_test
>> +}
>> +
>> +standard_testfile
>> +
>> +if [prepare_for_testing "failed to prepare" $testfile $srcfile \
>> + {debug pthreads}] {
>> + return -1
>> +}
>> +
>> +clean_restart ${binfile}
>> +
>> +gdb_test_no_output "set backtrace limit unlimited"
>> +
>> +test_live_inferior
>> +
>> +test_corefile
>> +
>> +test_gcore
>
>
Ping!
On 20/12/2023 10:40, Guinevere Larsen wrote:
> Ping!
>
> --
> Cheers,
> Guinevere Larsen
> She/Her/Hers
>
> On 04/12/2023 18:33, Guinevere Larsen wrote:
>> This patch is based on an out-of-tree patch that fedora has been
>> carrying for a while. It tests if GDB is able to properly unwind a
>> threaded program in the following situations:
>> * regular threads
>> * in a signal handler
>> * in a signal handler executing on an alternate stack
>>
>> And the final frame can either be in a syscall or in an infinite loop.
>>
>> The test works by running the inferior until a crash to generate a
>> corefile, or until right before the crash. Then applies a backtrace to
>> all threads to see if any frame can't be identified, and the order of
>> the threads in GDB. Finally, it goes thread by thread and tries to
>> collect a large part of the backtrace, to confirm that everything is
>> being unwound correctly.
>>
>> Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
>> Reviewed-By: Luis Machado <luis.machado@arm.com>
>>
>> ---
>>
>> Changes for v4:
>> * Luis mentioned that my strategy for starting the inferior didn't work
>> with native-extended testing. Changed to use runto_main instead
>> * Improved comments in the exp file based on Andrew's comments
>> * Minor cleanups with regards to TCL usage
>> ---
>> gdb/testsuite/gdb.threads/threadcrash.c | 443 ++++++++++++++++++++++
>> gdb/testsuite/gdb.threads/threadcrash.exp | 233 ++++++++++++
>> 2 files changed, 676 insertions(+)
>> create mode 100644 gdb/testsuite/gdb.threads/threadcrash.c
>> create mode 100644 gdb/testsuite/gdb.threads/threadcrash.exp
>>
>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.c
>> b/gdb/testsuite/gdb.threads/threadcrash.c
>> new file mode 100644
>> index 00000000000..e476ae7b07d
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.threads/threadcrash.c
>> @@ -0,0 +1,443 @@
>> +/* This testcase is part of GDB, the GNU debugger.
>> +
>> + Copyright 2023 Free Software Foundation, Inc.
>> +
>> + This program is free software; you can redistribute it and/or modify
>> + it under the terms of the GNU General Public License as published by
>> + the Free Software Foundation; either version 3 of the License, or
>> + (at your option) any later version.
>> +
>> + This program is distributed in the hope that it will be useful,
>> + but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + GNU General Public License for more details.
>> +
>> + You should have received a copy of the GNU General Public License
>> + along with this program. If not, see
>> <http://www.gnu.org/licenses/>. */
>> +
>> +#include <pthread.h>
>> +#include <assert.h>
>> +#include <stdlib.h>
>> +#include <signal.h>
>> +#include <unistd.h>
>> +
>> +/* The delay that the main thread gives once all the worker threads
>> have
>> + reached the barrier before the main thread enters the function on
>> which
>> + GDB will have placed a breakpoint. */
>> +
>> +#define MAIN_THREAD_DELAY 2
>> +
>> +/* The maximum time we allow this test program to run for before an
>> alarm
>> + signal is sent and everything will exit. */
>> +#define WATCHDOG_ALARM_TIME 600
>> +
>> +/* Aliases for the signals used within this script. Each signal
>> + corresponds to an action (from the FINAL_ACTION enum) that the
>> signal
>> + handler will perform. */
>> +
>> +#define SPIN_SIGNAL SIGUSR1
>> +#define SYSCALL_SIGNAL SIGUSR2
>> +
>> +/* Describe the final action that a thread should perform. */
>> +
>> +enum final_action
>> + {
>> + /* Thread should spin in an infinite loop. */
>> + SPIN = 0,
>> +
>> + /* Thread should block in a syscall. */
>> + SYSCALL,
>> +
>> + /* This is just a marker to allow for looping over the enum. */
>> + LAST_ACTION
>> + };
>> +
>> +/* Where should the thread perform this action? */
>> +
>> +enum exec_location
>> + {
>> + /* Just a normal thread, on a normal stack. */
>> + NORMAL = 0,
>> +
>> + /* In a signal handler, but use the normal stack. */
>> + SIGNAL_HANDLER,
>> +
>> + /* In a signal handler using an alternative stack. */
>> + SIGNAL_ALT_STACK,
>> +
>> + /* This is just a marker to allow for looping over the enum. */
>> + LAST_LOCACTION
>> + };
>> +
>> +/* A descriptor for a single thread job. We create a new thread for
>> each
>> + job_description. */
>> +
>> +struct job_description
>> +{
>> + /* What action should this thread perform. */
>> + enum final_action action;
>> +
>> + /* Where should the thread perform the action. */
>> + enum exec_location location;
>> +
>> + /* The actual thread handle, so we can join with the thread. */
>> + pthread_t thread;
>> +};
>> +
>> +/* A pthread barrier, used to (try) and synchronise the threads. */
>> +pthread_barrier_t global_barrier;
>> +
>> +/* Return a list of jobs, and place the length of the list in
>> *COUNT. */
>> +
>> +struct job_description *
>> +get_job_list (int *count)
>> +{
>> + /* The number of jobs. */
>> + int num = LAST_ACTION * LAST_LOCACTION;
>> +
>> + /* The uninitialised array of jobs. */
>> + struct job_description *list
>> + = malloc (num * sizeof (struct job_description));
>> + assert (list != NULL);
>> +
>> + /* Fill the array with all possible jobs. */
>> + for (int i = 0; i < (int) LAST_ACTION; ++i)
>> + for (int j = 0; j < (int) LAST_LOCACTION; ++j)
>> + {
>> + int idx = (i * LAST_LOCACTION) + j;
>> + list[idx].action = (enum final_action) i;
>> + list[idx].location = (enum exec_location) j;
>> + }
>> +
>> + /* Return the array of jobs. */
>> + *count = num;
>> + return list;
>> +}
>> +
>> +/* This function should never be called. If it is then an assertion
>> will
>> + trigger. */
>> +
>> +void
>> +assert_not_reached (void)
>> +{
>> + assert (0);
>> +}
>> +
>> +/* The function for a SPIN action. Just spins in a loop. The LOCATION
>> + argument exists so GDB can identify the expected context for this
>> + function. */
>> +
>> +void
>> +do_spin_task (enum exec_location location)
>> +{
>> + (void) location;
>> +
>> + /* Let everyone know that we're about to perform our action. */
>> + int res = pthread_barrier_wait (&global_barrier);
>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>> +
>> + while (1)
>> + {
>> + /* Nothing. */
>> + }
>> +}
>> +
>> +/* The function for a SYSCALL action. Just spins in a loop. The
>> LOCATION
>> + argument exists so GDB can identify the expected context for this
>> + function. */
>> +
>> +void
>> +do_syscall_task (enum exec_location location)
>> +{
>> + (void) location;
>> +
>> + /* Let everyone know that we're about to perform our action. */
>> + int res = pthread_barrier_wait (&global_barrier);
>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>> +
>> + sleep (600);
>> +}
>> +
>> +/* Return the required size for a sigaltstack. We start with a single
>> + page, but do check against the system defined minimums. We don't run
>> + much on the alternative stacks, so we don't need a huge one. */
>> +
>> +size_t
>> +get_stack_size (void)
>> +{
>> + size_t size = getpagesize (); /* Arbitrary starting size. */
>> + if (size < SIGSTKSZ)
>> + size = SIGSTKSZ;
>> + if (size < MINSIGSTKSZ)
>> + size = MINSIGSTKSZ;
>> + return size;
>> +}
>> +
>> +/* A descriptor for an alternative stack. */
>> +
>> +struct stack_descriptor
>> +{
>> + /* The base address of the alternative stack. This is the address
>> that
>> + must be freed to release the memory used by this stack. */
>> + void *base;
>> +
>> + /* The size of this alternative stack. Tracked just so we can
>> query this
>> + from GDB. */
>> + size_t size;
>> +};
>> +
>> +/* Install an alternative signal stack. Return a descriptor for the
>> newly
>> + allocated alternative stack. */
>> +
>> +struct stack_descriptor
>> +setup_alt_stack (void)
>> +{
>> + size_t stack_size = get_stack_size ();
>> +
>> + void *stack_area = malloc (stack_size);
>> +
>> + stack_t stk;
>> + stk.ss_sp = stack_area;
>> + stk.ss_flags = 0;
>> + stk.ss_size = stack_size;
>> +
>> + int res = sigaltstack (&stk, NULL);
>> + assert (res == 0);
>> +
>> + struct stack_descriptor desc;
>> + desc.base = stack_area;
>> + desc.size = stack_size;
>> +
>> + return desc;
>> +}
>> +
>> +/* Return true (non-zero) if we are currently on the alternative stack,
>> + otherwise, return false (zero). */
>> +
>> +int
>> +on_alt_stack_p (void)
>> +{
>> + stack_t stk;
>> + int res = sigaltstack (NULL, &stk);
>> + assert (res == 0);
>> +
>> + return (stk.ss_flags & SS_ONSTACK) != 0;
>> +}
>> +
>> +/* The signal handler function. All signals call here, so we use SIGNO
>> + (the signal that was delivered) to decide what action to
>> perform. This
>> + function might, or might not, have been called on an alternative
>> signal
>> + stack. */
>> +
>> +void
>> +signal_handler (int signo)
>> +{
>> + enum exec_location location
>> + = on_alt_stack_p () ? SIGNAL_ALT_STACK : SIGNAL_HANDLER;
>> +
>> + switch (signo)
>> + {
>> + case SPIN_SIGNAL:
>> + do_spin_task (location);
>> + break;
>> +
>> + case SYSCALL_SIGNAL:
>> + do_syscall_task (location);
>> + break;
>> +
>> + default:
>> + assert_not_reached ();
>> + }
>> +}
>> +
>> +/* The thread worker function. ARG is a job_description pointer which
>> + describes what this thread is expected to do. This function always
>> + returns a NULL pointer. */
>> +
>> +void *
>> +thread_function (void *arg)
>> +{
>> + struct job_description *job = (struct job_description *) arg;
>> + struct stack_descriptor desc = { NULL, 0 };
>> + int sa_flags = 0;
>> +
>> + switch (job->location)
>> + {
>> + case NORMAL:
>> + /* This thread performs the worker action on the current thread,
>> + select the correct worker function based on the requested
>> + action. */
>> + switch (job->action)
>> + {
>> + case SPIN:
>> + do_spin_task (NORMAL);
>> + break;
>> +
>> + case SYSCALL:
>> + do_syscall_task (NORMAL);
>> + break;
>> +
>> + default:
>> + assert_not_reached ();
>> + }
>> + break;
>> +
>> + case SIGNAL_ALT_STACK:
>> + /* This thread is to perform its action in a signal handler on
>> the
>> + alternative stack. Install the alternative stack now, and then
>> + fall through to the normal signal handler location code. */
>> + desc = setup_alt_stack ();
>> + assert (desc.base != NULL);
>> + assert (desc.size > 0);
>> + sa_flags = SA_ONSTACK;
>> +
>> + /* Fall through. */
>> + case SIGNAL_HANDLER:
>> + {
>> + /* This thread is to perform its action in a signal handler. We
>> + might have just installed an alternative signal stack. */
>> + int signo, res;
>> +
>> + /* Select the correct signal number so that the signal handler will
>> + perform the required action. */
>> + switch (job->action)
>> + {
>> + case SPIN:
>> + signo = SPIN_SIGNAL;
>> + break;
>> +
>> + case SYSCALL:
>> + signo = SYSCALL_SIGNAL;
>> + break;
>> +
>> + default:
>> + assert_not_reached ();
>> + }
>> +
>> + /* Now setup the signal handler. */
>> + struct sigaction sa;
>> + sa.sa_handler = signal_handler;
>> + sigfillset (&sa.sa_mask);
>> + sa.sa_flags = sa_flags;
>> + res = sigaction (signo, &sa, NULL);
>> + assert (res == 0);
>> +
>> + /* Send the signal to this thread. */
>> + res = pthread_kill (job->thread, signo);
>> + assert (res == 0);
>> + }
>> + break;
>> +
>> + default:
>> + assert_not_reached ();
>> + };
>> +
>> + /* Free the alt-stack if we allocated one, if not DESC.BASE will be
>> + NULL so this call is fine. */
>> + free (desc.base);
>> +
>> + /* Thread complete. */
>> + return NULL;
>> +}
>> +
>> +void
>> +start_job (struct job_description *job)
>> +{
>> + int res;
>> +
>> + res = pthread_create (&job->thread, NULL, thread_function, job);
>> + assert (res == 0);
>> +}
>> +
>> +/* Join with the thread for JOB. This will block until the thread
>> for JOB
>> + has finished. */
>> +
>> +void
>> +finalise_job (struct job_description *job)
>> +{
>> + int res;
>> + void *retval;
>> +
>> + res = pthread_join (job->thread, &retval);
>> + assert (res == 0);
>> + assert (retval == NULL);
>> +}
>> +
>> +/* Function that GDB can place a breakpoint on. */
>> +
>> +void
>> +breakpt (void)
>> +{
>> + /* Nothing. */
>> +}
>> +
>> +/* Function that triggers a crash, if the user has setup their
>> environment
>> + correctly this will dump a core file, which GDB can then
>> examine. */
>> +
>> +void
>> +crash_function (void)
>> +{
>> + volatile int *p = 0;
>> + volatile int n = *p;
>> + (void) n;
>> +}
>> +
>> +/* Entry point. */
>> +
>> +int
>> +main ()
>> +{
>> + int job_count, res;
>> + struct job_description *jobs = get_job_list (&job_count);
>> +
>> + /* This test is going to park some threads inside infinite loops.
>> Just
>> + in case this program is left running, install an alarm that
>> will cause
>> + everything to exit. */
>> + alarm (WATCHDOG_ALARM_TIME);
>> +
>> + /* We want each worker thread (of which there are JOB_COUNT) plus the
>> + main thread (hence + 1) to wait at the barrier. */
>> + res = pthread_barrier_init (&global_barrier, NULL, job_count + 1);
>> + assert (res == 0);
>> +
>> + /* Start all the jobs. */
>> + for (int i = 0; i < job_count; ++i)
>> + start_job (&jobs[i]);
>> +
>> + /* Notify all the worker threads that we're waiting for them. */
>> + res = pthread_barrier_wait (&global_barrier);
>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>> +
>> + /* All we know at this point is that all the worker threads have
>> reached
>> + the barrier, which is just before they perform their action.
>> But we
>> + really want them to start their action.
>> +
>> + There's really no way we can be 100% certain that the worker
>> threads
>> + have started their action, all we can do is wait for a short
>> while and
>> + hope that the machine we're running on is not too slow. */
>> + sleep (MAIN_THREAD_DELAY);
>> +
>> + /* A function that GDB can place a breakpoint on. By the time we get
>> + here we are as sure as we can be that all of the worker threads
>> have
>> + started and are in their worker action (spinning, or syscall). */
>> + breakpt ();
>> +
>> + /* If GDB is not attached then this function will cause a crash,
>> which
>> + can be used to dump a core file, which GDB can then analyse. */
>> + crash_function ();
>> +
>> + /* Due to the crash we never expect to get here. Plus the worker
>> actions
>> + never terminate. But for completeness, here's where we join
>> with all
>> + the worker threads. */
>> + for (int i = 0; i < job_count; ++i)
>> + finalise_job (&jobs[i]);
>> +
>> + /* Cleanup the barrier. */
>> + res = pthread_barrier_destroy (&global_barrier);
>> + assert (res == 0);
>> +
>> + /* And clean up the jobs list. */
>> + free (jobs);
>> +
>> + return 0;
>> +}
>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.exp
>> b/gdb/testsuite/gdb.threads/threadcrash.exp
>> new file mode 100644
>> index 00000000000..996e020d1e8
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.threads/threadcrash.exp
>> @@ -0,0 +1,233 @@
>> +# This testcase is part of GDB, the GNU debugger.
>> +
>> +# Copyright 2023 Free Software Foundation, Inc.
>> +
>> +# This program is free software; you can redistribute it and/or modify
>> +# it under the terms of the GNU General Public License as published by
>> +# the Free Software Foundation; either version 3 of the License, or
>> +# (at your option) any later version.
>> +#
>> +# This program is distributed in the hope that it will be useful,
>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> +# GNU General Public License for more details.
>> +#
>> +# You should have received a copy of the GNU General Public License
>> +# along with this program. If not, see <http://www.gnu.org/licenses/>.
>> +
>> +# This test case looks at GDB's ability to get correct backtraces for a
>> +# crashed inferior, recreating it from a live inferior, a corefile and
>> +# a gcore.
>> +
>> +
>> +# Check that the inferior has 7 threads, and return the number of
>> threads (7).
>> +# We return the thread count so that, even if there is some error in
>> the test,
>> +# the final log doesn't get flooded with failures.
>> +
>> +proc test_thread_count {} {
>> + set thread_count 0
>> +
>> + gdb_test_multiple "info threads" "getting thread count" -lbl {
>> + -re "Thread" {
>> + incr thread_count
>> + exp_continue
>> + }
>> + -re "$::gdb_prompt " {
>> + gdb_assert {$thread_count == 7}
>> + }
>> + }
>> +
>> + return $thread_count
>> +}
>> +
>> +# Use 'thread apply all backtrace' to check if all expected threads
>> +# are present, and stopped in the expected locations. Set the global
>> +# TEST_LIST to be the a list of regexps expected to match all the
>> +# threads. We generate it now so that the list is in the order that
>> +# GDB sees the threads.
>> +
>> +proc thread_apply_all {} {
>> + global test_list
>> +
>> + set test_list { }
>> +
>> + set unwind_fail false
>> +
>> + gdb_test_multiple "thread apply all backtrace" \
>> + "Get thread information" -lbl {
>> + -re "#\[0-9\]+\\\?\\\?\[^\n\]*" {
>> + set unwind_fail true
>> + exp_continue
>> + }
>> + -re "\[^\n\]*syscall_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
>> + lappend test_list [multi_line ".*sleep.*" \
>> + ".*do_syscall_task
>> .location=SIGNAL_ALT_STACK.*" \
>> + ".*signal_handler.*" \
>> + ".*signal handler called.*" \
>> + ".*pthread_kill.*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*syscall_task .location=SIGNAL_HANDLER\[^\n\]*" {
>> + lappend test_list [multi_line ".*sleep.*" \
>> + ".*do_syscall_task
>> .location=SIGNAL_HANDLER.*" \
>> + ".*signal_handler.*" \
>> + ".*signal handler called.*" \
>> + ".*pthread_kill.*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*syscall_task .location=NORMAL\[^\n\]*" {
>> + lappend test_list [multi_line ".*sleep.*" \
>> + ".*do_syscall_task .location=NORMAL.*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*spin_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
>> + lappend test_list [multi_line ".*do_spin_task
>> .location=SIGNAL_ALT_STACK.*" \
>> + ".*signal_handler.*" \
>> + ".*signal handler called.*" \
>> + ".*pthread_kill.*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*spin_task .location=SIGNAL_HANDLER\[^\n\]*" {
>> + lappend test_list [multi_line ".*do_spin_task
>> .location=SIGNAL_HANDLER.*" \
>> + ".*signal_handler.*" \
>> + ".*signal handler called.*" \
>> + ".*pthread_kill.*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*spin_task .location=NORMAL\[^\n\]*" {
>> + lappend test_list [multi_line ".*do_spin_task
>> .location=NORMAL..*" \
>> + ".*thread_function.*"]
>> + exp_continue
>> + }
>> + -re "\[^\n\]*main\[^\n\]*" {
>> + lappend test_list ".*main.*"
>> + exp_continue
>> + }
>> + -re "$::gdb_prompt " {
>> + pass $gdb_test_name
>> + }
>> + }
>> +
>> + gdb_assert {$unwind_fail == false}
>> +}
>> +
>> +# Perform all the tests we're interested in. They are:
>> +# * test if we have 7 threads
>> +# * Creating the list of backtraces for all threads seen
>> +# * testing if GDB recreated the full backtrace we expect for all
>> threads
>> +
>> +proc do_full_test {} {
>> + global test_list
>> + set thread_count [test_thread_count]
>> +
>> + thread_apply_all
>> +
>> + gdb_assert {$thread_count == [llength $test_list]}
>> +
>> + for {set i 0} {$i < $thread_count } {incr i} {
>> + set thread_num [expr [llength $test_list] - $i]
>> +
>> + gdb_test "thread apply $thread_num backtrace" [lindex $test_list
>> $i]
>> + }
>> +}
>> +
>> +# Do all preparation steps for running the corefile tests, then
>> +# call do_full_test to actually run the tests.
>> +
>> +proc_with_prefix test_live_inferior {} {
>> + gdb_test "handle SIGUSR1 nostop print pass" \
>> + ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>> + "setup SIGUSR1"
>> + gdb_test "handle SIGUSR2 nostop print pass" \
>> + ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>> + "setup SIGUSR2"
>> +
>> + if {![runto_main]} {
>> + return
>> + }
>> +
>> + gdb_breakpoint "breakpt"
>> + gdb_continue_to_breakpoint "running to breakpoint" ".*"
>> +
>> + do_full_test
>> +}
>> +
>> +# Do all preparation steps for running the corefile tests, then
>> +# call do_full_test to actually run the tests.
>> +
>> +proc_with_prefix test_corefile {} {
>> + set corefile [core_find $::binfile]
>> + if { $corefile == "" } {
>> + untested "couldn't generate corefile"
>> + return
>> + }
>> + set corefile [gdb_remote_download host $corefile]
>> +
>> + gdb_test "core-file $corefile" \
>> + "" \
>> + "loading_corefile" \
>> + "A program is being debugged already\\\. Kill it\\\? \\\(y
>> or n\\\) " \
>> + "y"
>> +
>> + do_full_test
>> +}
>> +
>> +# Do all preparation steps for running the gcore tests, then
>> +# call do_full_test to actually run the tests.
>> +
>> +proc_with_prefix test_gcore {} {
>> +
>> + clean_restart "$::binfile"
>> +
>> + gdb_test "handle SIGUSR1 nostop print pass" \
>> + ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>> + "setup SIGUSR1"
>> + gdb_test "handle SIGUSR2 nostop print pass" \
>> + ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>> + "setup SIGUSR2"
>> +
>> + if {![runto_main]} {
>> + return -1
>> + }
>> + gdb_test "continue" ".*Segmentation fault.*" "continue to crash"
>> +
>> + set gcore_name "${::binfile}.gcore"
>> + set gcore_supported [gdb_gcore_cmd "$gcore_name" "saving gcore"]
>> +
>> + if {!$gcore_supported} {
>> + unsupported "couldn't generate gcore file"
>> + return
>> + }
>> +
>> + set corefile [gdb_remote_download host $gcore_name]
>> +
>> + gdb_test "core-file $corefile" \
>> + "" \
>> + "loading_corefile" \
>> + "A program is being debugged already\\\. Kill it\\\? \\\(y
>> or n\\\) " \
>> + "y"
>> +
>> + do_full_test
>> +}
>> +
>> +standard_testfile
>> +
>> +if [prepare_for_testing "failed to prepare" $testfile $srcfile \
>> + {debug pthreads}] {
>> + return -1
>> +}
>> +
>> +clean_restart ${binfile}
>> +
>> +gdb_test_no_output "set backtrace limit unlimited"
>> +
>> +test_live_inferior
>> +
>> +test_corefile
>> +
>> +test_gcore
>
>
Ping!
On 09/01/2024 12:50, Guinevere Larsen wrote:
> Ping!
> On 20/12/2023 10:40, Guinevere Larsen wrote:
>> Ping!
>>
>> --
>> Cheers,
>> Guinevere Larsen
>> She/Her/Hers
>>
>> On 04/12/2023 18:33, Guinevere Larsen wrote:
>>> This patch is based on an out-of-tree patch that fedora has been
>>> carrying for a while. It tests if GDB is able to properly unwind a
>>> threaded program in the following situations:
>>> * regular threads
>>> * in a signal handler
>>> * in a signal handler executing on an alternate stack
>>>
>>> And the final frame can either be in a syscall or in an infinite loop.
>>>
>>> The test works by running the inferior until a crash to generate a
>>> corefile, or until right before the crash. Then applies a backtrace to
>>> all threads to see if any frame can't be identified, and the order of
>>> the threads in GDB. Finally, it goes thread by thread and tries to
>>> collect a large part of the backtrace, to confirm that everything is
>>> being unwound correctly.
>>>
>>> Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
>>> Reviewed-By: Luis Machado <luis.machado@arm.com>
>>>
>>> ---
>>>
>>> Changes for v4:
>>> * Luis mentioned that my strategy for starting the inferior didn't work
>>> with native-extended testing. Changed to use runto_main instead
>>> * Improved comments in the exp file based on Andrew's comments
>>> * Minor cleanups with regards to TCL usage
>>> ---
>>> gdb/testsuite/gdb.threads/threadcrash.c | 443
>>> ++++++++++++++++++++++
>>> gdb/testsuite/gdb.threads/threadcrash.exp | 233 ++++++++++++
>>> 2 files changed, 676 insertions(+)
>>> create mode 100644 gdb/testsuite/gdb.threads/threadcrash.c
>>> create mode 100644 gdb/testsuite/gdb.threads/threadcrash.exp
>>>
>>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.c
>>> b/gdb/testsuite/gdb.threads/threadcrash.c
>>> new file mode 100644
>>> index 00000000000..e476ae7b07d
>>> --- /dev/null
>>> +++ b/gdb/testsuite/gdb.threads/threadcrash.c
>>> @@ -0,0 +1,443 @@
>>> +/* This testcase is part of GDB, the GNU debugger.
>>> +
>>> + Copyright 2023 Free Software Foundation, Inc.
>>> +
>>> + This program is free software; you can redistribute it and/or
>>> modify
>>> + it under the terms of the GNU General Public License as
>>> published by
>>> + the Free Software Foundation; either version 3 of the License, or
>>> + (at your option) any later version.
>>> +
>>> + This program is distributed in the hope that it will be useful,
>>> + but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>>> + GNU General Public License for more details.
>>> +
>>> + You should have received a copy of the GNU General Public License
>>> + along with this program. If not, see
>>> <http://www.gnu.org/licenses/>. */
>>> +
>>> +#include <pthread.h>
>>> +#include <assert.h>
>>> +#include <stdlib.h>
>>> +#include <signal.h>
>>> +#include <unistd.h>
>>> +
>>> +/* The delay that the main thread gives once all the worker threads
>>> have
>>> + reached the barrier before the main thread enters the function
>>> on which
>>> + GDB will have placed a breakpoint. */
>>> +
>>> +#define MAIN_THREAD_DELAY 2
>>> +
>>> +/* The maximum time we allow this test program to run for before an
>>> alarm
>>> + signal is sent and everything will exit. */
>>> +#define WATCHDOG_ALARM_TIME 600
>>> +
>>> +/* Aliases for the signals used within this script. Each signal
>>> + corresponds to an action (from the FINAL_ACTION enum) that the
>>> signal
>>> + handler will perform. */
>>> +
>>> +#define SPIN_SIGNAL SIGUSR1
>>> +#define SYSCALL_SIGNAL SIGUSR2
>>> +
>>> +/* Describe the final action that a thread should perform. */
>>> +
>>> +enum final_action
>>> + {
>>> + /* Thread should spin in an infinite loop. */
>>> + SPIN = 0,
>>> +
>>> + /* Thread should block in a syscall. */
>>> + SYSCALL,
>>> +
>>> + /* This is just a marker to allow for looping over the enum. */
>>> + LAST_ACTION
>>> + };
>>> +
>>> +/* Where should the thread perform this action? */
>>> +
>>> +enum exec_location
>>> + {
>>> + /* Just a normal thread, on a normal stack. */
>>> + NORMAL = 0,
>>> +
>>> + /* In a signal handler, but use the normal stack. */
>>> + SIGNAL_HANDLER,
>>> +
>>> + /* In a signal handler using an alternative stack. */
>>> + SIGNAL_ALT_STACK,
>>> +
>>> + /* This is just a marker to allow for looping over the enum. */
>>> + LAST_LOCACTION
>>> + };
>>> +
>>> +/* A descriptor for a single thread job. We create a new thread
>>> for each
>>> + job_description. */
>>> +
>>> +struct job_description
>>> +{
>>> + /* What action should this thread perform. */
>>> + enum final_action action;
>>> +
>>> + /* Where should the thread perform the action. */
>>> + enum exec_location location;
>>> +
>>> + /* The actual thread handle, so we can join with the thread. */
>>> + pthread_t thread;
>>> +};
>>> +
>>> +/* A pthread barrier, used to (try) and synchronise the threads. */
>>> +pthread_barrier_t global_barrier;
>>> +
>>> +/* Return a list of jobs, and place the length of the list in
>>> *COUNT. */
>>> +
>>> +struct job_description *
>>> +get_job_list (int *count)
>>> +{
>>> + /* The number of jobs. */
>>> + int num = LAST_ACTION * LAST_LOCACTION;
>>> +
>>> + /* The uninitialised array of jobs. */
>>> + struct job_description *list
>>> + = malloc (num * sizeof (struct job_description));
>>> + assert (list != NULL);
>>> +
>>> + /* Fill the array with all possible jobs. */
>>> + for (int i = 0; i < (int) LAST_ACTION; ++i)
>>> + for (int j = 0; j < (int) LAST_LOCACTION; ++j)
>>> + {
>>> + int idx = (i * LAST_LOCACTION) + j;
>>> + list[idx].action = (enum final_action) i;
>>> + list[idx].location = (enum exec_location) j;
>>> + }
>>> +
>>> + /* Return the array of jobs. */
>>> + *count = num;
>>> + return list;
>>> +}
>>> +
>>> +/* This function should never be called. If it is then an
>>> assertion will
>>> + trigger. */
>>> +
>>> +void
>>> +assert_not_reached (void)
>>> +{
>>> + assert (0);
>>> +}
>>> +
>>> +/* The function for a SPIN action. Just spins in a loop. The LOCATION
>>> + argument exists so GDB can identify the expected context for this
>>> + function. */
>>> +
>>> +void
>>> +do_spin_task (enum exec_location location)
>>> +{
>>> + (void) location;
>>> +
>>> + /* Let everyone know that we're about to perform our action. */
>>> + int res = pthread_barrier_wait (&global_barrier);
>>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>>> +
>>> + while (1)
>>> + {
>>> + /* Nothing. */
>>> + }
>>> +}
>>> +
>>> +/* The function for a SYSCALL action. Just spins in a loop. The
>>> LOCATION
>>> + argument exists so GDB can identify the expected context for this
>>> + function. */
>>> +
>>> +void
>>> +do_syscall_task (enum exec_location location)
>>> +{
>>> + (void) location;
>>> +
>>> + /* Let everyone know that we're about to perform our action. */
>>> + int res = pthread_barrier_wait (&global_barrier);
>>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>>> +
>>> + sleep (600);
>>> +}
>>> +
>>> +/* Return the required size for a sigaltstack. We start with a single
>>> + page, but do check against the system defined minimums. We don't
>>> run
>>> + much on the alternative stacks, so we don't need a huge one. */
>>> +
>>> +size_t
>>> +get_stack_size (void)
>>> +{
>>> + size_t size = getpagesize (); /* Arbitrary starting size. */
>>> + if (size < SIGSTKSZ)
>>> + size = SIGSTKSZ;
>>> + if (size < MINSIGSTKSZ)
>>> + size = MINSIGSTKSZ;
>>> + return size;
>>> +}
>>> +
>>> +/* A descriptor for an alternative stack. */
>>> +
>>> +struct stack_descriptor
>>> +{
>>> + /* The base address of the alternative stack. This is the
>>> address that
>>> + must be freed to release the memory used by this stack. */
>>> + void *base;
>>> +
>>> + /* The size of this alternative stack. Tracked just so we can
>>> query this
>>> + from GDB. */
>>> + size_t size;
>>> +};
>>> +
>>> +/* Install an alternative signal stack. Return a descriptor for
>>> the newly
>>> + allocated alternative stack. */
>>> +
>>> +struct stack_descriptor
>>> +setup_alt_stack (void)
>>> +{
>>> + size_t stack_size = get_stack_size ();
>>> +
>>> + void *stack_area = malloc (stack_size);
>>> +
>>> + stack_t stk;
>>> + stk.ss_sp = stack_area;
>>> + stk.ss_flags = 0;
>>> + stk.ss_size = stack_size;
>>> +
>>> + int res = sigaltstack (&stk, NULL);
>>> + assert (res == 0);
>>> +
>>> + struct stack_descriptor desc;
>>> + desc.base = stack_area;
>>> + desc.size = stack_size;
>>> +
>>> + return desc;
>>> +}
>>> +
>>> +/* Return true (non-zero) if we are currently on the alternative
>>> stack,
>>> + otherwise, return false (zero). */
>>> +
>>> +int
>>> +on_alt_stack_p (void)
>>> +{
>>> + stack_t stk;
>>> + int res = sigaltstack (NULL, &stk);
>>> + assert (res == 0);
>>> +
>>> + return (stk.ss_flags & SS_ONSTACK) != 0;
>>> +}
>>> +
>>> +/* The signal handler function. All signals call here, so we use
>>> SIGNO
>>> + (the signal that was delivered) to decide what action to
>>> perform. This
>>> + function might, or might not, have been called on an alternative
>>> signal
>>> + stack. */
>>> +
>>> +void
>>> +signal_handler (int signo)
>>> +{
>>> + enum exec_location location
>>> + = on_alt_stack_p () ? SIGNAL_ALT_STACK : SIGNAL_HANDLER;
>>> +
>>> + switch (signo)
>>> + {
>>> + case SPIN_SIGNAL:
>>> + do_spin_task (location);
>>> + break;
>>> +
>>> + case SYSCALL_SIGNAL:
>>> + do_syscall_task (location);
>>> + break;
>>> +
>>> + default:
>>> + assert_not_reached ();
>>> + }
>>> +}
>>> +
>>> +/* The thread worker function. ARG is a job_description pointer which
>>> + describes what this thread is expected to do. This function always
>>> + returns a NULL pointer. */
>>> +
>>> +void *
>>> +thread_function (void *arg)
>>> +{
>>> + struct job_description *job = (struct job_description *) arg;
>>> + struct stack_descriptor desc = { NULL, 0 };
>>> + int sa_flags = 0;
>>> +
>>> + switch (job->location)
>>> + {
>>> + case NORMAL:
>>> + /* This thread performs the worker action on the current thread,
>>> + select the correct worker function based on the requested
>>> + action. */
>>> + switch (job->action)
>>> + {
>>> + case SPIN:
>>> + do_spin_task (NORMAL);
>>> + break;
>>> +
>>> + case SYSCALL:
>>> + do_syscall_task (NORMAL);
>>> + break;
>>> +
>>> + default:
>>> + assert_not_reached ();
>>> + }
>>> + break;
>>> +
>>> + case SIGNAL_ALT_STACK:
>>> + /* This thread is to perform its action in a signal handler
>>> on the
>>> + alternative stack. Install the alternative stack now, and then
>>> + fall through to the normal signal handler location code. */
>>> + desc = setup_alt_stack ();
>>> + assert (desc.base != NULL);
>>> + assert (desc.size > 0);
>>> + sa_flags = SA_ONSTACK;
>>> +
>>> + /* Fall through. */
>>> + case SIGNAL_HANDLER:
>>> + {
>>> + /* This thread is to perform its action in a signal handler. We
>>> + might have just installed an alternative signal stack. */
>>> + int signo, res;
>>> +
>>> + /* Select the correct signal number so that the signal handler
>>> will
>>> + perform the required action. */
>>> + switch (job->action)
>>> + {
>>> + case SPIN:
>>> + signo = SPIN_SIGNAL;
>>> + break;
>>> +
>>> + case SYSCALL:
>>> + signo = SYSCALL_SIGNAL;
>>> + break;
>>> +
>>> + default:
>>> + assert_not_reached ();
>>> + }
>>> +
>>> + /* Now setup the signal handler. */
>>> + struct sigaction sa;
>>> + sa.sa_handler = signal_handler;
>>> + sigfillset (&sa.sa_mask);
>>> + sa.sa_flags = sa_flags;
>>> + res = sigaction (signo, &sa, NULL);
>>> + assert (res == 0);
>>> +
>>> + /* Send the signal to this thread. */
>>> + res = pthread_kill (job->thread, signo);
>>> + assert (res == 0);
>>> + }
>>> + break;
>>> +
>>> + default:
>>> + assert_not_reached ();
>>> + };
>>> +
>>> + /* Free the alt-stack if we allocated one, if not DESC.BASE will be
>>> + NULL so this call is fine. */
>>> + free (desc.base);
>>> +
>>> + /* Thread complete. */
>>> + return NULL;
>>> +}
>>> +
>>> +void
>>> +start_job (struct job_description *job)
>>> +{
>>> + int res;
>>> +
>>> + res = pthread_create (&job->thread, NULL, thread_function, job);
>>> + assert (res == 0);
>>> +}
>>> +
>>> +/* Join with the thread for JOB. This will block until the thread
>>> for JOB
>>> + has finished. */
>>> +
>>> +void
>>> +finalise_job (struct job_description *job)
>>> +{
>>> + int res;
>>> + void *retval;
>>> +
>>> + res = pthread_join (job->thread, &retval);
>>> + assert (res == 0);
>>> + assert (retval == NULL);
>>> +}
>>> +
>>> +/* Function that GDB can place a breakpoint on. */
>>> +
>>> +void
>>> +breakpt (void)
>>> +{
>>> + /* Nothing. */
>>> +}
>>> +
>>> +/* Function that triggers a crash, if the user has setup their
>>> environment
>>> + correctly this will dump a core file, which GDB can then
>>> examine. */
>>> +
>>> +void
>>> +crash_function (void)
>>> +{
>>> + volatile int *p = 0;
>>> + volatile int n = *p;
>>> + (void) n;
>>> +}
>>> +
>>> +/* Entry point. */
>>> +
>>> +int
>>> +main ()
>>> +{
>>> + int job_count, res;
>>> + struct job_description *jobs = get_job_list (&job_count);
>>> +
>>> + /* This test is going to park some threads inside infinite
>>> loops. Just
>>> + in case this program is left running, install an alarm that
>>> will cause
>>> + everything to exit. */
>>> + alarm (WATCHDOG_ALARM_TIME);
>>> +
>>> + /* We want each worker thread (of which there are JOB_COUNT) plus
>>> the
>>> + main thread (hence + 1) to wait at the barrier. */
>>> + res = pthread_barrier_init (&global_barrier, NULL, job_count + 1);
>>> + assert (res == 0);
>>> +
>>> + /* Start all the jobs. */
>>> + for (int i = 0; i < job_count; ++i)
>>> + start_job (&jobs[i]);
>>> +
>>> + /* Notify all the worker threads that we're waiting for them. */
>>> + res = pthread_barrier_wait (&global_barrier);
>>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>>> +
>>> + /* All we know at this point is that all the worker threads have
>>> reached
>>> + the barrier, which is just before they perform their action.
>>> But we
>>> + really want them to start their action.
>>> +
>>> + There's really no way we can be 100% certain that the worker
>>> threads
>>> + have started their action, all we can do is wait for a short
>>> while and
>>> + hope that the machine we're running on is not too slow. */
>>> + sleep (MAIN_THREAD_DELAY);
>>> +
>>> + /* A function that GDB can place a breakpoint on. By the time we
>>> get
>>> + here we are as sure as we can be that all of the worker
>>> threads have
>>> + started and are in their worker action (spinning, or
>>> syscall). */
>>> + breakpt ();
>>> +
>>> + /* If GDB is not attached then this function will cause a crash,
>>> which
>>> + can be used to dump a core file, which GDB can then analyse. */
>>> + crash_function ();
>>> +
>>> + /* Due to the crash we never expect to get here. Plus the worker
>>> actions
>>> + never terminate. But for completeness, here's where we join
>>> with all
>>> + the worker threads. */
>>> + for (int i = 0; i < job_count; ++i)
>>> + finalise_job (&jobs[i]);
>>> +
>>> + /* Cleanup the barrier. */
>>> + res = pthread_barrier_destroy (&global_barrier);
>>> + assert (res == 0);
>>> +
>>> + /* And clean up the jobs list. */
>>> + free (jobs);
>>> +
>>> + return 0;
>>> +}
>>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.exp
>>> b/gdb/testsuite/gdb.threads/threadcrash.exp
>>> new file mode 100644
>>> index 00000000000..996e020d1e8
>>> --- /dev/null
>>> +++ b/gdb/testsuite/gdb.threads/threadcrash.exp
>>> @@ -0,0 +1,233 @@
>>> +# This testcase is part of GDB, the GNU debugger.
>>> +
>>> +# Copyright 2023 Free Software Foundation, Inc.
>>> +
>>> +# This program is free software; you can redistribute it and/or modify
>>> +# it under the terms of the GNU General Public License as published by
>>> +# the Free Software Foundation; either version 3 of the License, or
>>> +# (at your option) any later version.
>>> +#
>>> +# This program is distributed in the hope that it will be useful,
>>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>>> +# GNU General Public License for more details.
>>> +#
>>> +# You should have received a copy of the GNU General Public License
>>> +# along with this program. If not, see
>>> <http://www.gnu.org/licenses/>.
>>> +
>>> +# This test case looks at GDB's ability to get correct backtraces
>>> for a
>>> +# crashed inferior, recreating it from a live inferior, a corefile and
>>> +# a gcore.
>>> +
>>> +
>>> +# Check that the inferior has 7 threads, and return the number of
>>> threads (7).
>>> +# We return the thread count so that, even if there is some error
>>> in the test,
>>> +# the final log doesn't get flooded with failures.
>>> +
>>> +proc test_thread_count {} {
>>> + set thread_count 0
>>> +
>>> + gdb_test_multiple "info threads" "getting thread count" -lbl {
>>> + -re "Thread" {
>>> + incr thread_count
>>> + exp_continue
>>> + }
>>> + -re "$::gdb_prompt " {
>>> + gdb_assert {$thread_count == 7}
>>> + }
>>> + }
>>> +
>>> + return $thread_count
>>> +}
>>> +
>>> +# Use 'thread apply all backtrace' to check if all expected threads
>>> +# are present, and stopped in the expected locations. Set the global
>>> +# TEST_LIST to be the a list of regexps expected to match all the
>>> +# threads. We generate it now so that the list is in the order that
>>> +# GDB sees the threads.
>>> +
>>> +proc thread_apply_all {} {
>>> + global test_list
>>> +
>>> + set test_list { }
>>> +
>>> + set unwind_fail false
>>> +
>>> + gdb_test_multiple "thread apply all backtrace" \
>>> + "Get thread information" -lbl {
>>> + -re "#\[0-9\]+\\\?\\\?\[^\n\]*" {
>>> + set unwind_fail true
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*syscall_task
>>> .location=SIGNAL_ALT_STACK\[^\n\]*" {
>>> + lappend test_list [multi_line ".*sleep.*" \
>>> + ".*do_syscall_task
>>> .location=SIGNAL_ALT_STACK.*" \
>>> + ".*signal_handler.*" \
>>> + ".*signal handler called.*" \
>>> + ".*pthread_kill.*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*syscall_task .location=SIGNAL_HANDLER\[^\n\]*" {
>>> + lappend test_list [multi_line ".*sleep.*" \
>>> + ".*do_syscall_task
>>> .location=SIGNAL_HANDLER.*" \
>>> + ".*signal_handler.*" \
>>> + ".*signal handler called.*" \
>>> + ".*pthread_kill.*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*syscall_task .location=NORMAL\[^\n\]*" {
>>> + lappend test_list [multi_line ".*sleep.*" \
>>> + ".*do_syscall_task .location=NORMAL.*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*spin_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
>>> + lappend test_list [multi_line ".*do_spin_task
>>> .location=SIGNAL_ALT_STACK.*" \
>>> + ".*signal_handler.*" \
>>> + ".*signal handler called.*" \
>>> + ".*pthread_kill.*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*spin_task .location=SIGNAL_HANDLER\[^\n\]*" {
>>> + lappend test_list [multi_line ".*do_spin_task
>>> .location=SIGNAL_HANDLER.*" \
>>> + ".*signal_handler.*" \
>>> + ".*signal handler called.*" \
>>> + ".*pthread_kill.*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*spin_task .location=NORMAL\[^\n\]*" {
>>> + lappend test_list [multi_line ".*do_spin_task
>>> .location=NORMAL..*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*main\[^\n\]*" {
>>> + lappend test_list ".*main.*"
>>> + exp_continue
>>> + }
>>> + -re "$::gdb_prompt " {
>>> + pass $gdb_test_name
>>> + }
>>> + }
>>> +
>>> + gdb_assert {$unwind_fail == false}
>>> +}
>>> +
>>> +# Perform all the tests we're interested in. They are:
>>> +# * test if we have 7 threads
>>> +# * Creating the list of backtraces for all threads seen
>>> +# * testing if GDB recreated the full backtrace we expect for all
>>> threads
>>> +
>>> +proc do_full_test {} {
>>> + global test_list
>>> + set thread_count [test_thread_count]
>>> +
>>> + thread_apply_all
>>> +
>>> + gdb_assert {$thread_count == [llength $test_list]}
>>> +
>>> + for {set i 0} {$i < $thread_count } {incr i} {
>>> + set thread_num [expr [llength $test_list] - $i]
>>> +
>>> + gdb_test "thread apply $thread_num backtrace" [lindex
>>> $test_list $i]
>>> + }
>>> +}
>>> +
>>> +# Do all preparation steps for running the corefile tests, then
>>> +# call do_full_test to actually run the tests.
>>> +
>>> +proc_with_prefix test_live_inferior {} {
>>> + gdb_test "handle SIGUSR1 nostop print pass" \
>>> + ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>>> + "setup SIGUSR1"
>>> + gdb_test "handle SIGUSR2 nostop print pass" \
>>> + ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>>> + "setup SIGUSR2"
>>> +
>>> + if {![runto_main]} {
>>> + return
>>> + }
>>> +
>>> + gdb_breakpoint "breakpt"
>>> + gdb_continue_to_breakpoint "running to breakpoint" ".*"
>>> +
>>> + do_full_test
>>> +}
>>> +
>>> +# Do all preparation steps for running the corefile tests, then
>>> +# call do_full_test to actually run the tests.
>>> +
>>> +proc_with_prefix test_corefile {} {
>>> + set corefile [core_find $::binfile]
>>> + if { $corefile == "" } {
>>> + untested "couldn't generate corefile"
>>> + return
>>> + }
>>> + set corefile [gdb_remote_download host $corefile]
>>> +
>>> + gdb_test "core-file $corefile" \
>>> + "" \
>>> + "loading_corefile" \
>>> + "A program is being debugged already\\\. Kill it\\\?
>>> \\\(y or n\\\) " \
>>> + "y"
>>> +
>>> + do_full_test
>>> +}
>>> +
>>> +# Do all preparation steps for running the gcore tests, then
>>> +# call do_full_test to actually run the tests.
>>> +
>>> +proc_with_prefix test_gcore {} {
>>> +
>>> + clean_restart "$::binfile"
>>> +
>>> + gdb_test "handle SIGUSR1 nostop print pass" \
>>> + ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>>> + "setup SIGUSR1"
>>> + gdb_test "handle SIGUSR2 nostop print pass" \
>>> + ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>>> + "setup SIGUSR2"
>>> +
>>> + if {![runto_main]} {
>>> + return -1
>>> + }
>>> + gdb_test "continue" ".*Segmentation fault.*" "continue to crash"
>>> +
>>> + set gcore_name "${::binfile}.gcore"
>>> + set gcore_supported [gdb_gcore_cmd "$gcore_name" "saving gcore"]
>>> +
>>> + if {!$gcore_supported} {
>>> + unsupported "couldn't generate gcore file"
>>> + return
>>> + }
>>> +
>>> + set corefile [gdb_remote_download host $gcore_name]
>>> +
>>> + gdb_test "core-file $corefile" \
>>> + "" \
>>> + "loading_corefile" \
>>> + "A program is being debugged already\\\. Kill it\\\?
>>> \\\(y or n\\\) " \
>>> + "y"
>>> +
>>> + do_full_test
>>> +}
>>> +
>>> +standard_testfile
>>> +
>>> +if [prepare_for_testing "failed to prepare" $testfile $srcfile \
>>> + {debug pthreads}] {
>>> + return -1
>>> +}
>>> +
>>> +clean_restart ${binfile}
>>> +
>>> +gdb_test_no_output "set backtrace limit unlimited"
>>> +
>>> +test_live_inferior
>>> +
>>> +test_corefile
>>> +
>>> +test_gcore
>>
>>
>
Ping!
On 09/01/2024 12:50, Guinevere Larsen wrote:
> Ping!
> On 20/12/2023 10:40, Guinevere Larsen wrote:
>> Ping!
>>
>> --
>> Cheers,
>> Guinevere Larsen
>> She/Her/Hers
>>
>> On 04/12/2023 18:33, Guinevere Larsen wrote:
>>> This patch is based on an out-of-tree patch that fedora has been
>>> carrying for a while. It tests if GDB is able to properly unwind a
>>> threaded program in the following situations:
>>> * regular threads
>>> * in a signal handler
>>> * in a signal handler executing on an alternate stack
>>>
>>> And the final frame can either be in a syscall or in an infinite loop.
>>>
>>> The test works by running the inferior until a crash to generate a
>>> corefile, or until right before the crash. Then applies a backtrace to
>>> all threads to see if any frame can't be identified, and the order of
>>> the threads in GDB. Finally, it goes thread by thread and tries to
>>> collect a large part of the backtrace, to confirm that everything is
>>> being unwound correctly.
>>>
>>> Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
>>> Reviewed-By: Luis Machado <luis.machado@arm.com>
>>>
>>> ---
>>>
>>> Changes for v4:
>>> * Luis mentioned that my strategy for starting the inferior didn't work
>>> with native-extended testing. Changed to use runto_main instead
>>> * Improved comments in the exp file based on Andrew's comments
>>> * Minor cleanups with regards to TCL usage
>>> ---
>>> gdb/testsuite/gdb.threads/threadcrash.c | 443
>>> ++++++++++++++++++++++
>>> gdb/testsuite/gdb.threads/threadcrash.exp | 233 ++++++++++++
>>> 2 files changed, 676 insertions(+)
>>> create mode 100644 gdb/testsuite/gdb.threads/threadcrash.c
>>> create mode 100644 gdb/testsuite/gdb.threads/threadcrash.exp
>>>
>>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.c
>>> b/gdb/testsuite/gdb.threads/threadcrash.c
>>> new file mode 100644
>>> index 00000000000..e476ae7b07d
>>> --- /dev/null
>>> +++ b/gdb/testsuite/gdb.threads/threadcrash.c
>>> @@ -0,0 +1,443 @@
>>> +/* This testcase is part of GDB, the GNU debugger.
>>> +
>>> + Copyright 2023 Free Software Foundation, Inc.
>>> +
>>> + This program is free software; you can redistribute it and/or
>>> modify
>>> + it under the terms of the GNU General Public License as
>>> published by
>>> + the Free Software Foundation; either version 3 of the License, or
>>> + (at your option) any later version.
>>> +
>>> + This program is distributed in the hope that it will be useful,
>>> + but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>>> + GNU General Public License for more details.
>>> +
>>> + You should have received a copy of the GNU General Public License
>>> + along with this program. If not, see
>>> <http://www.gnu.org/licenses/>. */
>>> +
>>> +#include <pthread.h>
>>> +#include <assert.h>
>>> +#include <stdlib.h>
>>> +#include <signal.h>
>>> +#include <unistd.h>
>>> +
>>> +/* The delay that the main thread gives once all the worker threads
>>> have
>>> + reached the barrier before the main thread enters the function
>>> on which
>>> + GDB will have placed a breakpoint. */
>>> +
>>> +#define MAIN_THREAD_DELAY 2
>>> +
>>> +/* The maximum time we allow this test program to run for before an
>>> alarm
>>> + signal is sent and everything will exit. */
>>> +#define WATCHDOG_ALARM_TIME 600
>>> +
>>> +/* Aliases for the signals used within this script. Each signal
>>> + corresponds to an action (from the FINAL_ACTION enum) that the
>>> signal
>>> + handler will perform. */
>>> +
>>> +#define SPIN_SIGNAL SIGUSR1
>>> +#define SYSCALL_SIGNAL SIGUSR2
>>> +
>>> +/* Describe the final action that a thread should perform. */
>>> +
>>> +enum final_action
>>> + {
>>> + /* Thread should spin in an infinite loop. */
>>> + SPIN = 0,
>>> +
>>> + /* Thread should block in a syscall. */
>>> + SYSCALL,
>>> +
>>> + /* This is just a marker to allow for looping over the enum. */
>>> + LAST_ACTION
>>> + };
>>> +
>>> +/* Where should the thread perform this action? */
>>> +
>>> +enum exec_location
>>> + {
>>> + /* Just a normal thread, on a normal stack. */
>>> + NORMAL = 0,
>>> +
>>> + /* In a signal handler, but use the normal stack. */
>>> + SIGNAL_HANDLER,
>>> +
>>> + /* In a signal handler using an alternative stack. */
>>> + SIGNAL_ALT_STACK,
>>> +
>>> + /* This is just a marker to allow for looping over the enum. */
>>> + LAST_LOCACTION
>>> + };
>>> +
>>> +/* A descriptor for a single thread job. We create a new thread
>>> for each
>>> + job_description. */
>>> +
>>> +struct job_description
>>> +{
>>> + /* What action should this thread perform. */
>>> + enum final_action action;
>>> +
>>> + /* Where should the thread perform the action. */
>>> + enum exec_location location;
>>> +
>>> + /* The actual thread handle, so we can join with the thread. */
>>> + pthread_t thread;
>>> +};
>>> +
>>> +/* A pthread barrier, used to (try) and synchronise the threads. */
>>> +pthread_barrier_t global_barrier;
>>> +
>>> +/* Return a list of jobs, and place the length of the list in
>>> *COUNT. */
>>> +
>>> +struct job_description *
>>> +get_job_list (int *count)
>>> +{
>>> + /* The number of jobs. */
>>> + int num = LAST_ACTION * LAST_LOCACTION;
>>> +
>>> + /* The uninitialised array of jobs. */
>>> + struct job_description *list
>>> + = malloc (num * sizeof (struct job_description));
>>> + assert (list != NULL);
>>> +
>>> + /* Fill the array with all possible jobs. */
>>> + for (int i = 0; i < (int) LAST_ACTION; ++i)
>>> + for (int j = 0; j < (int) LAST_LOCACTION; ++j)
>>> + {
>>> + int idx = (i * LAST_LOCACTION) + j;
>>> + list[idx].action = (enum final_action) i;
>>> + list[idx].location = (enum exec_location) j;
>>> + }
>>> +
>>> + /* Return the array of jobs. */
>>> + *count = num;
>>> + return list;
>>> +}
>>> +
>>> +/* This function should never be called. If it is then an
>>> assertion will
>>> + trigger. */
>>> +
>>> +void
>>> +assert_not_reached (void)
>>> +{
>>> + assert (0);
>>> +}
>>> +
>>> +/* The function for a SPIN action. Just spins in a loop. The LOCATION
>>> + argument exists so GDB can identify the expected context for this
>>> + function. */
>>> +
>>> +void
>>> +do_spin_task (enum exec_location location)
>>> +{
>>> + (void) location;
>>> +
>>> + /* Let everyone know that we're about to perform our action. */
>>> + int res = pthread_barrier_wait (&global_barrier);
>>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>>> +
>>> + while (1)
>>> + {
>>> + /* Nothing. */
>>> + }
>>> +}
>>> +
>>> +/* The function for a SYSCALL action. Just spins in a loop. The
>>> LOCATION
>>> + argument exists so GDB can identify the expected context for this
>>> + function. */
>>> +
>>> +void
>>> +do_syscall_task (enum exec_location location)
>>> +{
>>> + (void) location;
>>> +
>>> + /* Let everyone know that we're about to perform our action. */
>>> + int res = pthread_barrier_wait (&global_barrier);
>>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>>> +
>>> + sleep (600);
>>> +}
>>> +
>>> +/* Return the required size for a sigaltstack. We start with a single
>>> + page, but do check against the system defined minimums. We don't
>>> run
>>> + much on the alternative stacks, so we don't need a huge one. */
>>> +
>>> +size_t
>>> +get_stack_size (void)
>>> +{
>>> + size_t size = getpagesize (); /* Arbitrary starting size. */
>>> + if (size < SIGSTKSZ)
>>> + size = SIGSTKSZ;
>>> + if (size < MINSIGSTKSZ)
>>> + size = MINSIGSTKSZ;
>>> + return size;
>>> +}
>>> +
>>> +/* A descriptor for an alternative stack. */
>>> +
>>> +struct stack_descriptor
>>> +{
>>> + /* The base address of the alternative stack. This is the
>>> address that
>>> + must be freed to release the memory used by this stack. */
>>> + void *base;
>>> +
>>> + /* The size of this alternative stack. Tracked just so we can
>>> query this
>>> + from GDB. */
>>> + size_t size;
>>> +};
>>> +
>>> +/* Install an alternative signal stack. Return a descriptor for
>>> the newly
>>> + allocated alternative stack. */
>>> +
>>> +struct stack_descriptor
>>> +setup_alt_stack (void)
>>> +{
>>> + size_t stack_size = get_stack_size ();
>>> +
>>> + void *stack_area = malloc (stack_size);
>>> +
>>> + stack_t stk;
>>> + stk.ss_sp = stack_area;
>>> + stk.ss_flags = 0;
>>> + stk.ss_size = stack_size;
>>> +
>>> + int res = sigaltstack (&stk, NULL);
>>> + assert (res == 0);
>>> +
>>> + struct stack_descriptor desc;
>>> + desc.base = stack_area;
>>> + desc.size = stack_size;
>>> +
>>> + return desc;
>>> +}
>>> +
>>> +/* Return true (non-zero) if we are currently on the alternative
>>> stack,
>>> + otherwise, return false (zero). */
>>> +
>>> +int
>>> +on_alt_stack_p (void)
>>> +{
>>> + stack_t stk;
>>> + int res = sigaltstack (NULL, &stk);
>>> + assert (res == 0);
>>> +
>>> + return (stk.ss_flags & SS_ONSTACK) != 0;
>>> +}
>>> +
>>> +/* The signal handler function. All signals call here, so we use
>>> SIGNO
>>> + (the signal that was delivered) to decide what action to
>>> perform. This
>>> + function might, or might not, have been called on an alternative
>>> signal
>>> + stack. */
>>> +
>>> +void
>>> +signal_handler (int signo)
>>> +{
>>> + enum exec_location location
>>> + = on_alt_stack_p () ? SIGNAL_ALT_STACK : SIGNAL_HANDLER;
>>> +
>>> + switch (signo)
>>> + {
>>> + case SPIN_SIGNAL:
>>> + do_spin_task (location);
>>> + break;
>>> +
>>> + case SYSCALL_SIGNAL:
>>> + do_syscall_task (location);
>>> + break;
>>> +
>>> + default:
>>> + assert_not_reached ();
>>> + }
>>> +}
>>> +
>>> +/* The thread worker function. ARG is a job_description pointer which
>>> + describes what this thread is expected to do. This function always
>>> + returns a NULL pointer. */
>>> +
>>> +void *
>>> +thread_function (void *arg)
>>> +{
>>> + struct job_description *job = (struct job_description *) arg;
>>> + struct stack_descriptor desc = { NULL, 0 };
>>> + int sa_flags = 0;
>>> +
>>> + switch (job->location)
>>> + {
>>> + case NORMAL:
>>> + /* This thread performs the worker action on the current thread,
>>> + select the correct worker function based on the requested
>>> + action. */
>>> + switch (job->action)
>>> + {
>>> + case SPIN:
>>> + do_spin_task (NORMAL);
>>> + break;
>>> +
>>> + case SYSCALL:
>>> + do_syscall_task (NORMAL);
>>> + break;
>>> +
>>> + default:
>>> + assert_not_reached ();
>>> + }
>>> + break;
>>> +
>>> + case SIGNAL_ALT_STACK:
>>> + /* This thread is to perform its action in a signal handler
>>> on the
>>> + alternative stack. Install the alternative stack now, and then
>>> + fall through to the normal signal handler location code. */
>>> + desc = setup_alt_stack ();
>>> + assert (desc.base != NULL);
>>> + assert (desc.size > 0);
>>> + sa_flags = SA_ONSTACK;
>>> +
>>> + /* Fall through. */
>>> + case SIGNAL_HANDLER:
>>> + {
>>> + /* This thread is to perform its action in a signal handler. We
>>> + might have just installed an alternative signal stack. */
>>> + int signo, res;
>>> +
>>> + /* Select the correct signal number so that the signal handler
>>> will
>>> + perform the required action. */
>>> + switch (job->action)
>>> + {
>>> + case SPIN:
>>> + signo = SPIN_SIGNAL;
>>> + break;
>>> +
>>> + case SYSCALL:
>>> + signo = SYSCALL_SIGNAL;
>>> + break;
>>> +
>>> + default:
>>> + assert_not_reached ();
>>> + }
>>> +
>>> + /* Now setup the signal handler. */
>>> + struct sigaction sa;
>>> + sa.sa_handler = signal_handler;
>>> + sigfillset (&sa.sa_mask);
>>> + sa.sa_flags = sa_flags;
>>> + res = sigaction (signo, &sa, NULL);
>>> + assert (res == 0);
>>> +
>>> + /* Send the signal to this thread. */
>>> + res = pthread_kill (job->thread, signo);
>>> + assert (res == 0);
>>> + }
>>> + break;
>>> +
>>> + default:
>>> + assert_not_reached ();
>>> + };
>>> +
>>> + /* Free the alt-stack if we allocated one, if not DESC.BASE will be
>>> + NULL so this call is fine. */
>>> + free (desc.base);
>>> +
>>> + /* Thread complete. */
>>> + return NULL;
>>> +}
>>> +
>>> +void
>>> +start_job (struct job_description *job)
>>> +{
>>> + int res;
>>> +
>>> + res = pthread_create (&job->thread, NULL, thread_function, job);
>>> + assert (res == 0);
>>> +}
>>> +
>>> +/* Join with the thread for JOB. This will block until the thread
>>> for JOB
>>> + has finished. */
>>> +
>>> +void
>>> +finalise_job (struct job_description *job)
>>> +{
>>> + int res;
>>> + void *retval;
>>> +
>>> + res = pthread_join (job->thread, &retval);
>>> + assert (res == 0);
>>> + assert (retval == NULL);
>>> +}
>>> +
>>> +/* Function that GDB can place a breakpoint on. */
>>> +
>>> +void
>>> +breakpt (void)
>>> +{
>>> + /* Nothing. */
>>> +}
>>> +
>>> +/* Function that triggers a crash, if the user has setup their
>>> environment
>>> + correctly this will dump a core file, which GDB can then
>>> examine. */
>>> +
>>> +void
>>> +crash_function (void)
>>> +{
>>> + volatile int *p = 0;
>>> + volatile int n = *p;
>>> + (void) n;
>>> +}
>>> +
>>> +/* Entry point. */
>>> +
>>> +int
>>> +main ()
>>> +{
>>> + int job_count, res;
>>> + struct job_description *jobs = get_job_list (&job_count);
>>> +
>>> + /* This test is going to park some threads inside infinite
>>> loops. Just
>>> + in case this program is left running, install an alarm that
>>> will cause
>>> + everything to exit. */
>>> + alarm (WATCHDOG_ALARM_TIME);
>>> +
>>> + /* We want each worker thread (of which there are JOB_COUNT) plus
>>> the
>>> + main thread (hence + 1) to wait at the barrier. */
>>> + res = pthread_barrier_init (&global_barrier, NULL, job_count + 1);
>>> + assert (res == 0);
>>> +
>>> + /* Start all the jobs. */
>>> + for (int i = 0; i < job_count; ++i)
>>> + start_job (&jobs[i]);
>>> +
>>> + /* Notify all the worker threads that we're waiting for them. */
>>> + res = pthread_barrier_wait (&global_barrier);
>>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>>> +
>>> + /* All we know at this point is that all the worker threads have
>>> reached
>>> + the barrier, which is just before they perform their action.
>>> But we
>>> + really want them to start their action.
>>> +
>>> + There's really no way we can be 100% certain that the worker
>>> threads
>>> + have started their action, all we can do is wait for a short
>>> while and
>>> + hope that the machine we're running on is not too slow. */
>>> + sleep (MAIN_THREAD_DELAY);
>>> +
>>> + /* A function that GDB can place a breakpoint on. By the time we
>>> get
>>> + here we are as sure as we can be that all of the worker
>>> threads have
>>> + started and are in their worker action (spinning, or
>>> syscall). */
>>> + breakpt ();
>>> +
>>> + /* If GDB is not attached then this function will cause a crash,
>>> which
>>> + can be used to dump a core file, which GDB can then analyse. */
>>> + crash_function ();
>>> +
>>> + /* Due to the crash we never expect to get here. Plus the worker
>>> actions
>>> + never terminate. But for completeness, here's where we join
>>> with all
>>> + the worker threads. */
>>> + for (int i = 0; i < job_count; ++i)
>>> + finalise_job (&jobs[i]);
>>> +
>>> + /* Cleanup the barrier. */
>>> + res = pthread_barrier_destroy (&global_barrier);
>>> + assert (res == 0);
>>> +
>>> + /* And clean up the jobs list. */
>>> + free (jobs);
>>> +
>>> + return 0;
>>> +}
>>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.exp
>>> b/gdb/testsuite/gdb.threads/threadcrash.exp
>>> new file mode 100644
>>> index 00000000000..996e020d1e8
>>> --- /dev/null
>>> +++ b/gdb/testsuite/gdb.threads/threadcrash.exp
>>> @@ -0,0 +1,233 @@
>>> +# This testcase is part of GDB, the GNU debugger.
>>> +
>>> +# Copyright 2023 Free Software Foundation, Inc.
>>> +
>>> +# This program is free software; you can redistribute it and/or modify
>>> +# it under the terms of the GNU General Public License as published by
>>> +# the Free Software Foundation; either version 3 of the License, or
>>> +# (at your option) any later version.
>>> +#
>>> +# This program is distributed in the hope that it will be useful,
>>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>>> +# GNU General Public License for more details.
>>> +#
>>> +# You should have received a copy of the GNU General Public License
>>> +# along with this program. If not, see
>>> <http://www.gnu.org/licenses/>.
>>> +
>>> +# This test case looks at GDB's ability to get correct backtraces
>>> for a
>>> +# crashed inferior, recreating it from a live inferior, a corefile and
>>> +# a gcore.
>>> +
>>> +
>>> +# Check that the inferior has 7 threads, and return the number of
>>> threads (7).
>>> +# We return the thread count so that, even if there is some error
>>> in the test,
>>> +# the final log doesn't get flooded with failures.
>>> +
>>> +proc test_thread_count {} {
>>> + set thread_count 0
>>> +
>>> + gdb_test_multiple "info threads" "getting thread count" -lbl {
>>> + -re "Thread" {
>>> + incr thread_count
>>> + exp_continue
>>> + }
>>> + -re "$::gdb_prompt " {
>>> + gdb_assert {$thread_count == 7}
>>> + }
>>> + }
>>> +
>>> + return $thread_count
>>> +}
>>> +
>>> +# Use 'thread apply all backtrace' to check if all expected threads
>>> +# are present, and stopped in the expected locations. Set the global
>>> +# TEST_LIST to be the a list of regexps expected to match all the
>>> +# threads. We generate it now so that the list is in the order that
>>> +# GDB sees the threads.
>>> +
>>> +proc thread_apply_all {} {
>>> + global test_list
>>> +
>>> + set test_list { }
>>> +
>>> + set unwind_fail false
>>> +
>>> + gdb_test_multiple "thread apply all backtrace" \
>>> + "Get thread information" -lbl {
>>> + -re "#\[0-9\]+\\\?\\\?\[^\n\]*" {
>>> + set unwind_fail true
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*syscall_task
>>> .location=SIGNAL_ALT_STACK\[^\n\]*" {
>>> + lappend test_list [multi_line ".*sleep.*" \
>>> + ".*do_syscall_task
>>> .location=SIGNAL_ALT_STACK.*" \
>>> + ".*signal_handler.*" \
>>> + ".*signal handler called.*" \
>>> + ".*pthread_kill.*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*syscall_task .location=SIGNAL_HANDLER\[^\n\]*" {
>>> + lappend test_list [multi_line ".*sleep.*" \
>>> + ".*do_syscall_task
>>> .location=SIGNAL_HANDLER.*" \
>>> + ".*signal_handler.*" \
>>> + ".*signal handler called.*" \
>>> + ".*pthread_kill.*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*syscall_task .location=NORMAL\[^\n\]*" {
>>> + lappend test_list [multi_line ".*sleep.*" \
>>> + ".*do_syscall_task .location=NORMAL.*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*spin_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
>>> + lappend test_list [multi_line ".*do_spin_task
>>> .location=SIGNAL_ALT_STACK.*" \
>>> + ".*signal_handler.*" \
>>> + ".*signal handler called.*" \
>>> + ".*pthread_kill.*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*spin_task .location=SIGNAL_HANDLER\[^\n\]*" {
>>> + lappend test_list [multi_line ".*do_spin_task
>>> .location=SIGNAL_HANDLER.*" \
>>> + ".*signal_handler.*" \
>>> + ".*signal handler called.*" \
>>> + ".*pthread_kill.*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*spin_task .location=NORMAL\[^\n\]*" {
>>> + lappend test_list [multi_line ".*do_spin_task
>>> .location=NORMAL..*" \
>>> + ".*thread_function.*"]
>>> + exp_continue
>>> + }
>>> + -re "\[^\n\]*main\[^\n\]*" {
>>> + lappend test_list ".*main.*"
>>> + exp_continue
>>> + }
>>> + -re "$::gdb_prompt " {
>>> + pass $gdb_test_name
>>> + }
>>> + }
>>> +
>>> + gdb_assert {$unwind_fail == false}
>>> +}
>>> +
>>> +# Perform all the tests we're interested in. They are:
>>> +# * test if we have 7 threads
>>> +# * Creating the list of backtraces for all threads seen
>>> +# * testing if GDB recreated the full backtrace we expect for all
>>> threads
>>> +
>>> +proc do_full_test {} {
>>> + global test_list
>>> + set thread_count [test_thread_count]
>>> +
>>> + thread_apply_all
>>> +
>>> + gdb_assert {$thread_count == [llength $test_list]}
>>> +
>>> + for {set i 0} {$i < $thread_count } {incr i} {
>>> + set thread_num [expr [llength $test_list] - $i]
>>> +
>>> + gdb_test "thread apply $thread_num backtrace" [lindex
>>> $test_list $i]
>>> + }
>>> +}
>>> +
>>> +# Do all preparation steps for running the corefile tests, then
>>> +# call do_full_test to actually run the tests.
>>> +
>>> +proc_with_prefix test_live_inferior {} {
>>> + gdb_test "handle SIGUSR1 nostop print pass" \
>>> + ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>>> + "setup SIGUSR1"
>>> + gdb_test "handle SIGUSR2 nostop print pass" \
>>> + ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>>> + "setup SIGUSR2"
>>> +
>>> + if {![runto_main]} {
>>> + return
>>> + }
>>> +
>>> + gdb_breakpoint "breakpt"
>>> + gdb_continue_to_breakpoint "running to breakpoint" ".*"
>>> +
>>> + do_full_test
>>> +}
>>> +
>>> +# Do all preparation steps for running the corefile tests, then
>>> +# call do_full_test to actually run the tests.
>>> +
>>> +proc_with_prefix test_corefile {} {
>>> + set corefile [core_find $::binfile]
>>> + if { $corefile == "" } {
>>> + untested "couldn't generate corefile"
>>> + return
>>> + }
>>> + set corefile [gdb_remote_download host $corefile]
>>> +
>>> + gdb_test "core-file $corefile" \
>>> + "" \
>>> + "loading_corefile" \
>>> + "A program is being debugged already\\\. Kill it\\\?
>>> \\\(y or n\\\) " \
>>> + "y"
>>> +
>>> + do_full_test
>>> +}
>>> +
>>> +# Do all preparation steps for running the gcore tests, then
>>> +# call do_full_test to actually run the tests.
>>> +
>>> +proc_with_prefix test_gcore {} {
>>> +
>>> + clean_restart "$::binfile"
>>> +
>>> + gdb_test "handle SIGUSR1 nostop print pass" \
>>> + ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>>> + "setup SIGUSR1"
>>> + gdb_test "handle SIGUSR2 nostop print pass" \
>>> + ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>>> + "setup SIGUSR2"
>>> +
>>> + if {![runto_main]} {
>>> + return -1
>>> + }
>>> + gdb_test "continue" ".*Segmentation fault.*" "continue to crash"
>>> +
>>> + set gcore_name "${::binfile}.gcore"
>>> + set gcore_supported [gdb_gcore_cmd "$gcore_name" "saving gcore"]
>>> +
>>> + if {!$gcore_supported} {
>>> + unsupported "couldn't generate gcore file"
>>> + return
>>> + }
>>> +
>>> + set corefile [gdb_remote_download host $gcore_name]
>>> +
>>> + gdb_test "core-file $corefile" \
>>> + "" \
>>> + "loading_corefile" \
>>> + "A program is being debugged already\\\. Kill it\\\?
>>> \\\(y or n\\\) " \
>>> + "y"
>>> +
>>> + do_full_test
>>> +}
>>> +
>>> +standard_testfile
>>> +
>>> +if [prepare_for_testing "failed to prepare" $testfile $srcfile \
>>> + {debug pthreads}] {
>>> + return -1
>>> +}
>>> +
>>> +clean_restart ${binfile}
>>> +
>>> +gdb_test_no_output "set backtrace limit unlimited"
>>> +
>>> +test_live_inferior
>>> +
>>> +test_corefile
>>> +
>>> +test_gcore
>>
>>
>
Hi Guinevere,
Sorry for the delay.
On 1/24/24 09:34, Guinevere Larsen wrote:
> Ping!
> On 09/01/2024 12:50, Guinevere Larsen wrote:
>> Ping!
>> On 20/12/2023 10:40, Guinevere Larsen wrote:
>>> Ping!
>>>
>>> --
>>> Cheers,
>>> Guinevere Larsen
>>> She/Her/Hers
>>>
>>> On 04/12/2023 18:33, Guinevere Larsen wrote:
>>>> This patch is based on an out-of-tree patch that fedora has been
>>>> carrying for a while. It tests if GDB is able to properly unwind a
>>>> threaded program in the following situations:
>>>> * regular threads
>>>> * in a signal handler
>>>> * in a signal handler executing on an alternate stack
>>>>
>>>> And the final frame can either be in a syscall or in an infinite loop.
>>>>
>>>> The test works by running the inferior until a crash to generate a
>>>> corefile, or until right before the crash. Then applies a backtrace to
>>>> all threads to see if any frame can't be identified, and the order of
>>>> the threads in GDB. Finally, it goes thread by thread and tries to
>>>> collect a large part of the backtrace, to confirm that everything is
>>>> being unwound correctly.
>>>>
>>>> Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
>>>> Reviewed-By: Luis Machado <luis.machado@arm.com>
>>>>
>>>> ---
>>>>
>>>> Changes for v4:
>>>> * Luis mentioned that my strategy for starting the inferior didn't work
>>>> with native-extended testing. Changed to use runto_main instead
>>>> * Improved comments in the exp file based on Andrew's comments
>>>> * Minor cleanups with regards to TCL usage
>>>> ---
>>>> gdb/testsuite/gdb.threads/threadcrash.c | 443 ++++++++++++++++++++++
>>>> gdb/testsuite/gdb.threads/threadcrash.exp | 233 ++++++++++++
>>>> 2 files changed, 676 insertions(+)
>>>> create mode 100644 gdb/testsuite/gdb.threads/threadcrash.c
>>>> create mode 100644 gdb/testsuite/gdb.threads/threadcrash.exp
>>>>
>>>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.c b/gdb/testsuite/gdb.threads/threadcrash.c
>>>> new file mode 100644
>>>> index 00000000000..e476ae7b07d
>>>> --- /dev/null
>>>> +++ b/gdb/testsuite/gdb.threads/threadcrash.c
>>>> @@ -0,0 +1,443 @@
>>>> +/* This testcase is part of GDB, the GNU debugger.
>>>> +
>>>> + Copyright 2023 Free Software Foundation, Inc.
>>>> +
>>>> + This program is free software; you can redistribute it and/or modify
>>>> + it under the terms of the GNU General Public License as published by
>>>> + the Free Software Foundation; either version 3 of the License, or
>>>> + (at your option) any later version.
>>>> +
>>>> + This program is distributed in the hope that it will be useful,
>>>> + but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>>>> + GNU General Public License for more details.
>>>> +
>>>> + You should have received a copy of the GNU General Public License
>>>> + along with this program. If not, see <http://www.gnu.org/licenses/>. */
>>>> +
>>>> +#include <pthread.h>
>>>> +#include <assert.h>
>>>> +#include <stdlib.h>
>>>> +#include <signal.h>
>>>> +#include <unistd.h>
>>>> +
>>>> +/* The delay that the main thread gives once all the worker threads have
>>>> + reached the barrier before the main thread enters the function on which
>>>> + GDB will have placed a breakpoint. */
>>>> +
>>>> +#define MAIN_THREAD_DELAY 2
>>>> +
>>>> +/* The maximum time we allow this test program to run for before an alarm
>>>> + signal is sent and everything will exit. */
>>>> +#define WATCHDOG_ALARM_TIME 600
>>>> +
>>>> +/* Aliases for the signals used within this script. Each signal
>>>> + corresponds to an action (from the FINAL_ACTION enum) that the signal
>>>> + handler will perform. */
>>>> +
>>>> +#define SPIN_SIGNAL SIGUSR1
>>>> +#define SYSCALL_SIGNAL SIGUSR2
>>>> +
>>>> +/* Describe the final action that a thread should perform. */
>>>> +
>>>> +enum final_action
>>>> + {
>>>> + /* Thread should spin in an infinite loop. */
>>>> + SPIN = 0,
>>>> +
>>>> + /* Thread should block in a syscall. */
>>>> + SYSCALL,
>>>> +
>>>> + /* This is just a marker to allow for looping over the enum. */
>>>> + LAST_ACTION
>>>> + };
>>>> +
>>>> +/* Where should the thread perform this action? */
>>>> +
>>>> +enum exec_location
>>>> + {
>>>> + /* Just a normal thread, on a normal stack. */
>>>> + NORMAL = 0,
>>>> +
>>>> + /* In a signal handler, but use the normal stack. */
>>>> + SIGNAL_HANDLER,
>>>> +
>>>> + /* In a signal handler using an alternative stack. */
>>>> + SIGNAL_ALT_STACK,
>>>> +
>>>> + /* This is just a marker to allow for looping over the enum. */
>>>> + LAST_LOCACTION
>>>> + };
>>>> +
>>>> +/* A descriptor for a single thread job. We create a new thread for each
>>>> + job_description. */
>>>> +
>>>> +struct job_description
>>>> +{
>>>> + /* What action should this thread perform. */
>>>> + enum final_action action;
>>>> +
>>>> + /* Where should the thread perform the action. */
>>>> + enum exec_location location;
>>>> +
>>>> + /* The actual thread handle, so we can join with the thread. */
>>>> + pthread_t thread;
>>>> +};
>>>> +
>>>> +/* A pthread barrier, used to (try) and synchronise the threads. */
>>>> +pthread_barrier_t global_barrier;
>>>> +
>>>> +/* Return a list of jobs, and place the length of the list in *COUNT. */
>>>> +
>>>> +struct job_description *
>>>> +get_job_list (int *count)
>>>> +{
>>>> + /* The number of jobs. */
>>>> + int num = LAST_ACTION * LAST_LOCACTION;
>>>> +
>>>> + /* The uninitialised array of jobs. */
>>>> + struct job_description *list
>>>> + = malloc (num * sizeof (struct job_description));
>>>> + assert (list != NULL);
>>>> +
>>>> + /* Fill the array with all possible jobs. */
>>>> + for (int i = 0; i < (int) LAST_ACTION; ++i)
>>>> + for (int j = 0; j < (int) LAST_LOCACTION; ++j)
>>>> + {
>>>> + int idx = (i * LAST_LOCACTION) + j;
>>>> + list[idx].action = (enum final_action) i;
>>>> + list[idx].location = (enum exec_location) j;
>>>> + }
>>>> +
>>>> + /* Return the array of jobs. */
>>>> + *count = num;
>>>> + return list;
>>>> +}
>>>> +
>>>> +/* This function should never be called. If it is then an assertion will
>>>> + trigger. */
>>>> +
>>>> +void
>>>> +assert_not_reached (void)
>>>> +{
>>>> + assert (0);
>>>> +}
>>>> +
>>>> +/* The function for a SPIN action. Just spins in a loop. The LOCATION
>>>> + argument exists so GDB can identify the expected context for this
>>>> + function. */
>>>> +
>>>> +void
>>>> +do_spin_task (enum exec_location location)
>>>> +{
>>>> + (void) location;
>>>> +
>>>> + /* Let everyone know that we're about to perform our action. */
>>>> + int res = pthread_barrier_wait (&global_barrier);
>>>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>>>> +
>>>> + while (1)
>>>> + {
>>>> + /* Nothing. */
>>>> + }
>>>> +}
>>>> +
>>>> +/* The function for a SYSCALL action. Just spins in a loop. The LOCATION
>>>> + argument exists so GDB can identify the expected context for this
>>>> + function. */
>>>> +
>>>> +void
>>>> +do_syscall_task (enum exec_location location)
>>>> +{
>>>> + (void) location;
>>>> +
>>>> + /* Let everyone know that we're about to perform our action. */
>>>> + int res = pthread_barrier_wait (&global_barrier);
>>>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>>>> +
>>>> + sleep (600);
>>>> +}
>>>> +
>>>> +/* Return the required size for a sigaltstack. We start with a single
>>>> + page, but do check against the system defined minimums. We don't run
>>>> + much on the alternative stacks, so we don't need a huge one. */
>>>> +
>>>> +size_t
>>>> +get_stack_size (void)
>>>> +{
>>>> + size_t size = getpagesize (); /* Arbitrary starting size. */
>>>> + if (size < SIGSTKSZ)
>>>> + size = SIGSTKSZ;
>>>> + if (size < MINSIGSTKSZ)
>>>> + size = MINSIGSTKSZ;
>>>> + return size;
>>>> +}
>>>> +
>>>> +/* A descriptor for an alternative stack. */
>>>> +
>>>> +struct stack_descriptor
>>>> +{
>>>> + /* The base address of the alternative stack. This is the address that
>>>> + must be freed to release the memory used by this stack. */
>>>> + void *base;
>>>> +
>>>> + /* The size of this alternative stack. Tracked just so we can query this
>>>> + from GDB. */
>>>> + size_t size;
>>>> +};
>>>> +
>>>> +/* Install an alternative signal stack. Return a descriptor for the newly
>>>> + allocated alternative stack. */
>>>> +
>>>> +struct stack_descriptor
>>>> +setup_alt_stack (void)
>>>> +{
>>>> + size_t stack_size = get_stack_size ();
>>>> +
>>>> + void *stack_area = malloc (stack_size);
>>>> +
>>>> + stack_t stk;
>>>> + stk.ss_sp = stack_area;
>>>> + stk.ss_flags = 0;
>>>> + stk.ss_size = stack_size;
>>>> +
>>>> + int res = sigaltstack (&stk, NULL);
>>>> + assert (res == 0);
>>>> +
>>>> + struct stack_descriptor desc;
>>>> + desc.base = stack_area;
>>>> + desc.size = stack_size;
>>>> +
>>>> + return desc;
>>>> +}
>>>> +
>>>> +/* Return true (non-zero) if we are currently on the alternative stack,
>>>> + otherwise, return false (zero). */
>>>> +
>>>> +int
>>>> +on_alt_stack_p (void)
>>>> +{
>>>> + stack_t stk;
>>>> + int res = sigaltstack (NULL, &stk);
>>>> + assert (res == 0);
>>>> +
>>>> + return (stk.ss_flags & SS_ONSTACK) != 0;
>>>> +}
>>>> +
>>>> +/* The signal handler function. All signals call here, so we use SIGNO
>>>> + (the signal that was delivered) to decide what action to perform. This
>>>> + function might, or might not, have been called on an alternative signal
>>>> + stack. */
>>>> +
>>>> +void
>>>> +signal_handler (int signo)
>>>> +{
>>>> + enum exec_location location
>>>> + = on_alt_stack_p () ? SIGNAL_ALT_STACK : SIGNAL_HANDLER;
>>>> +
>>>> + switch (signo)
>>>> + {
>>>> + case SPIN_SIGNAL:
>>>> + do_spin_task (location);
>>>> + break;
>>>> +
>>>> + case SYSCALL_SIGNAL:
>>>> + do_syscall_task (location);
>>>> + break;
>>>> +
>>>> + default:
>>>> + assert_not_reached ();
>>>> + }
>>>> +}
>>>> +
>>>> +/* The thread worker function. ARG is a job_description pointer which
>>>> + describes what this thread is expected to do. This function always
>>>> + returns a NULL pointer. */
>>>> +
>>>> +void *
>>>> +thread_function (void *arg)
>>>> +{
>>>> + struct job_description *job = (struct job_description *) arg;
>>>> + struct stack_descriptor desc = { NULL, 0 };
>>>> + int sa_flags = 0;
>>>> +
>>>> + switch (job->location)
>>>> + {
>>>> + case NORMAL:
>>>> + /* This thread performs the worker action on the current thread,
>>>> + select the correct worker function based on the requested
>>>> + action. */
>>>> + switch (job->action)
>>>> + {
>>>> + case SPIN:
>>>> + do_spin_task (NORMAL);
>>>> + break;
>>>> +
>>>> + case SYSCALL:
>>>> + do_syscall_task (NORMAL);
>>>> + break;
>>>> +
>>>> + default:
>>>> + assert_not_reached ();
>>>> + }
>>>> + break;
>>>> +
>>>> + case SIGNAL_ALT_STACK:
>>>> + /* This thread is to perform its action in a signal handler on the
>>>> + alternative stack. Install the alternative stack now, and then
>>>> + fall through to the normal signal handler location code. */
>>>> + desc = setup_alt_stack ();
>>>> + assert (desc.base != NULL);
>>>> + assert (desc.size > 0);
>>>> + sa_flags = SA_ONSTACK;
>>>> +
>>>> + /* Fall through. */
>>>> + case SIGNAL_HANDLER:
>>>> + {
>>>> + /* This thread is to perform its action in a signal handler. We
>>>> + might have just installed an alternative signal stack. */
>>>> + int signo, res;
>>>> +
>>>> + /* Select the correct signal number so that the signal handler will
>>>> + perform the required action. */
>>>> + switch (job->action)
>>>> + {
>>>> + case SPIN:
>>>> + signo = SPIN_SIGNAL;
>>>> + break;
>>>> +
>>>> + case SYSCALL:
>>>> + signo = SYSCALL_SIGNAL;
>>>> + break;
>>>> +
>>>> + default:
>>>> + assert_not_reached ();
>>>> + }
>>>> +
>>>> + /* Now setup the signal handler. */
>>>> + struct sigaction sa;
>>>> + sa.sa_handler = signal_handler;
>>>> + sigfillset (&sa.sa_mask);
>>>> + sa.sa_flags = sa_flags;
>>>> + res = sigaction (signo, &sa, NULL);
>>>> + assert (res == 0);
>>>> +
>>>> + /* Send the signal to this thread. */
>>>> + res = pthread_kill (job->thread, signo);
>>>> + assert (res == 0);
>>>> + }
>>>> + break;
>>>> +
>>>> + default:
>>>> + assert_not_reached ();
>>>> + };
>>>> +
>>>> + /* Free the alt-stack if we allocated one, if not DESC.BASE will be
>>>> + NULL so this call is fine. */
>>>> + free (desc.base);
>>>> +
>>>> + /* Thread complete. */
>>>> + return NULL;
>>>> +}
>>>> +
>>>> +void
>>>> +start_job (struct job_description *job)
>>>> +{
>>>> + int res;
>>>> +
>>>> + res = pthread_create (&job->thread, NULL, thread_function, job);
>>>> + assert (res == 0);
>>>> +}
>>>> +
>>>> +/* Join with the thread for JOB. This will block until the thread for JOB
>>>> + has finished. */
>>>> +
>>>> +void
>>>> +finalise_job (struct job_description *job)
>>>> +{
>>>> + int res;
>>>> + void *retval;
>>>> +
>>>> + res = pthread_join (job->thread, &retval);
>>>> + assert (res == 0);
>>>> + assert (retval == NULL);
>>>> +}
>>>> +
>>>> +/* Function that GDB can place a breakpoint on. */
>>>> +
>>>> +void
>>>> +breakpt (void)
>>>> +{
>>>> + /* Nothing. */
>>>> +}
>>>> +
>>>> +/* Function that triggers a crash, if the user has setup their environment
>>>> + correctly this will dump a core file, which GDB can then examine. */
>>>> +
>>>> +void
>>>> +crash_function (void)
>>>> +{
>>>> + volatile int *p = 0;
>>>> + volatile int n = *p;
>>>> + (void) n;
>>>> +}
>>>> +
>>>> +/* Entry point. */
>>>> +
>>>> +int
>>>> +main ()
>>>> +{
>>>> + int job_count, res;
>>>> + struct job_description *jobs = get_job_list (&job_count);
>>>> +
>>>> + /* This test is going to park some threads inside infinite loops. Just
>>>> + in case this program is left running, install an alarm that will cause
>>>> + everything to exit. */
>>>> + alarm (WATCHDOG_ALARM_TIME);
>>>> +
>>>> + /* We want each worker thread (of which there are JOB_COUNT) plus the
>>>> + main thread (hence + 1) to wait at the barrier. */
>>>> + res = pthread_barrier_init (&global_barrier, NULL, job_count + 1);
>>>> + assert (res == 0);
>>>> +
>>>> + /* Start all the jobs. */
>>>> + for (int i = 0; i < job_count; ++i)
>>>> + start_job (&jobs[i]);
>>>> +
>>>> + /* Notify all the worker threads that we're waiting for them. */
>>>> + res = pthread_barrier_wait (&global_barrier);
>>>> + assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
>>>> +
>>>> + /* All we know at this point is that all the worker threads have reached
>>>> + the barrier, which is just before they perform their action. But we
>>>> + really want them to start their action.
>>>> +
>>>> + There's really no way we can be 100% certain that the worker threads
>>>> + have started their action, all we can do is wait for a short while and
>>>> + hope that the machine we're running on is not too slow. */
>>>> + sleep (MAIN_THREAD_DELAY);
>>>> +
>>>> + /* A function that GDB can place a breakpoint on. By the time we get
>>>> + here we are as sure as we can be that all of the worker threads have
>>>> + started and are in their worker action (spinning, or syscall). */
>>>> + breakpt ();
>>>> +
>>>> + /* If GDB is not attached then this function will cause a crash, which
>>>> + can be used to dump a core file, which GDB can then analyse. */
>>>> + crash_function ();
>>>> +
>>>> + /* Due to the crash we never expect to get here. Plus the worker actions
>>>> + never terminate. But for completeness, here's where we join with all
>>>> + the worker threads. */
>>>> + for (int i = 0; i < job_count; ++i)
>>>> + finalise_job (&jobs[i]);
>>>> +
>>>> + /* Cleanup the barrier. */
>>>> + res = pthread_barrier_destroy (&global_barrier);
>>>> + assert (res == 0);
>>>> +
>>>> + /* And clean up the jobs list. */
>>>> + free (jobs);
>>>> +
>>>> + return 0;
>>>> +}
>>>> diff --git a/gdb/testsuite/gdb.threads/threadcrash.exp b/gdb/testsuite/gdb.threads/threadcrash.exp
>>>> new file mode 100644
>>>> index 00000000000..996e020d1e8
>>>> --- /dev/null
>>>> +++ b/gdb/testsuite/gdb.threads/threadcrash.exp
>>>> @@ -0,0 +1,233 @@
>>>> +# This testcase is part of GDB, the GNU debugger.
>>>> +
>>>> +# Copyright 2023 Free Software Foundation, Inc.
>>>> +
>>>> +# This program is free software; you can redistribute it and/or modify
>>>> +# it under the terms of the GNU General Public License as published by
>>>> +# the Free Software Foundation; either version 3 of the License, or
>>>> +# (at your option) any later version.
>>>> +#
>>>> +# This program is distributed in the hope that it will be useful,
>>>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>>>> +# GNU General Public License for more details.
>>>> +#
>>>> +# You should have received a copy of the GNU General Public License
>>>> +# along with this program. If not, see <http://www.gnu.org/licenses/>.
>>>> +
>>>> +# This test case looks at GDB's ability to get correct backtraces for a
>>>> +# crashed inferior, recreating it from a live inferior, a corefile and
>>>> +# a gcore.
>>>> +
>>>> +
>>>> +# Check that the inferior has 7 threads, and return the number of threads (7).
>>>> +# We return the thread count so that, even if there is some error in the test,
>>>> +# the final log doesn't get flooded with failures.
>>>> +
>>>> +proc test_thread_count {} {
>>>> + set thread_count 0
>>>> +
>>>> + gdb_test_multiple "info threads" "getting thread count" -lbl {
>>>> + -re "Thread" {
>>>> + incr thread_count
>>>> + exp_continue
>>>> + }
>>>> + -re "$::gdb_prompt " {
>>>> + gdb_assert {$thread_count == 7}
>>>> + }
>>>> + }
>>>> +
>>>> + return $thread_count
>>>> +}
>>>> +
>>>> +# Use 'thread apply all backtrace' to check if all expected threads
>>>> +# are present, and stopped in the expected locations. Set the global
>>>> +# TEST_LIST to be the a list of regexps expected to match all the
>>>> +# threads. We generate it now so that the list is in the order that
>>>> +# GDB sees the threads.
>>>> +
>>>> +proc thread_apply_all {} {
>>>> + global test_list
>>>> +
>>>> + set test_list { }
>>>> +
>>>> + set unwind_fail false
>>>> +
>>>> + gdb_test_multiple "thread apply all backtrace" \
>>>> + "Get thread information" -lbl {
>>>> + -re "#\[0-9\]+\\\?\\\?\[^\n\]*" {
>>>> + set unwind_fail true
>>>> + exp_continue
>>>> + }
>>>> + -re "\[^\n\]*syscall_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
>>>> + lappend test_list [multi_line ".*sleep.*" \
>>>> + ".*do_syscall_task .location=SIGNAL_ALT_STACK.*" \
>>>> + ".*signal_handler.*" \
>>>> + ".*signal handler called.*" \
>>>> + ".*pthread_kill.*" \
>>>> + ".*thread_function.*"]
>>>> + exp_continue
>>>> + }
>>>> + -re "\[^\n\]*syscall_task .location=SIGNAL_HANDLER\[^\n\]*" {
>>>> + lappend test_list [multi_line ".*sleep.*" \
>>>> + ".*do_syscall_task .location=SIGNAL_HANDLER.*" \
>>>> + ".*signal_handler.*" \
>>>> + ".*signal handler called.*" \
>>>> + ".*pthread_kill.*" \
>>>> + ".*thread_function.*"]
>>>> + exp_continue
>>>> + }
>>>> + -re "\[^\n\]*syscall_task .location=NORMAL\[^\n\]*" {
>>>> + lappend test_list [multi_line ".*sleep.*" \
>>>> + ".*do_syscall_task .location=NORMAL.*" \
>>>> + ".*thread_function.*"]
>>>> + exp_continue
>>>> + }
>>>> + -re "\[^\n\]*spin_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
>>>> + lappend test_list [multi_line ".*do_spin_task .location=SIGNAL_ALT_STACK.*" \
>>>> + ".*signal_handler.*" \
>>>> + ".*signal handler called.*" \
>>>> + ".*pthread_kill.*" \
>>>> + ".*thread_function.*"]
>>>> + exp_continue
>>>> + }
>>>> + -re "\[^\n\]*spin_task .location=SIGNAL_HANDLER\[^\n\]*" {
>>>> + lappend test_list [multi_line ".*do_spin_task .location=SIGNAL_HANDLER.*" \
>>>> + ".*signal_handler.*" \
>>>> + ".*signal handler called.*" \
>>>> + ".*pthread_kill.*" \
>>>> + ".*thread_function.*"]
>>>> + exp_continue
>>>> + }
>>>> + -re "\[^\n\]*spin_task .location=NORMAL\[^\n\]*" {
>>>> + lappend test_list [multi_line ".*do_spin_task .location=NORMAL..*" \
>>>> + ".*thread_function.*"]
>>>> + exp_continue
>>>> + }
>>>> + -re "\[^\n\]*main\[^\n\]*" {
>>>> + lappend test_list ".*main.*"
>>>> + exp_continue
>>>> + }
>>>> + -re "$::gdb_prompt " {
>>>> + pass $gdb_test_name
>>>> + }
>>>> + }
>>>> +
>>>> + gdb_assert {$unwind_fail == false}
>>>> +}
>>>> +
>>>> +# Perform all the tests we're interested in. They are:
>>>> +# * test if we have 7 threads
>>>> +# * Creating the list of backtraces for all threads seen
>>>> +# * testing if GDB recreated the full backtrace we expect for all threads
>>>> +
>>>> +proc do_full_test {} {
>>>> + global test_list
>>>> + set thread_count [test_thread_count]
>>>> +
>>>> + thread_apply_all
>>>> +
>>>> + gdb_assert {$thread_count == [llength $test_list]}
>>>> +
>>>> + for {set i 0} {$i < $thread_count } {incr i} {
>>>> + set thread_num [expr [llength $test_list] - $i]
>>>> +
>>>> + gdb_test "thread apply $thread_num backtrace" [lindex $test_list $i]
>>>> + }
>>>> +}
>>>> +
>>>> +# Do all preparation steps for running the corefile tests, then
>>>> +# call do_full_test to actually run the tests.
>>>> +
>>>> +proc_with_prefix test_live_inferior {} {
>>>> + gdb_test "handle SIGUSR1 nostop print pass" \
>>>> + ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>>>> + "setup SIGUSR1"
>>>> + gdb_test "handle SIGUSR2 nostop print pass" \
>>>> + ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>>>> + "setup SIGUSR2"
>>>> +
>>>> + if {![runto_main]} {
>>>> + return
>>>> + }
>>>> +
>>>> + gdb_breakpoint "breakpt"
>>>> + gdb_continue_to_breakpoint "running to breakpoint" ".*"
>>>> +
>>>> + do_full_test
>>>> +}
>>>> +
>>>> +# Do all preparation steps for running the corefile tests, then
>>>> +# call do_full_test to actually run the tests.
>>>> +
>>>> +proc_with_prefix test_corefile {} {
>>>> + set corefile [core_find $::binfile]
>>>> + if { $corefile == "" } {
>>>> + untested "couldn't generate corefile"
>>>> + return
>>>> + }
>>>> + set corefile [gdb_remote_download host $corefile]
>>>> +
>>>> + gdb_test "core-file $corefile" \
>>>> + "" \
>>>> + "loading_corefile" \
>>>> + "A program is being debugged already\\\. Kill it\\\? \\\(y or n\\\) " \
>>>> + "y"
>>>> +
>>>> + do_full_test
>>>> +}
>>>> +
>>>> +# Do all preparation steps for running the gcore tests, then
>>>> +# call do_full_test to actually run the tests.
>>>> +
>>>> +proc_with_prefix test_gcore {} {
>>>> +
>>>> + clean_restart "$::binfile"
>>>> +
>>>> + gdb_test "handle SIGUSR1 nostop print pass" \
>>>> + ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
>>>> + "setup SIGUSR1"
>>>> + gdb_test "handle SIGUSR2 nostop print pass" \
>>>> + ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
>>>> + "setup SIGUSR2"
>>>> +
>>>> + if {![runto_main]} {
>>>> + return -1
>>>> + }
>>>> + gdb_test "continue" ".*Segmentation fault.*" "continue to crash"
>>>> +
>>>> + set gcore_name "${::binfile}.gcore"
>>>> + set gcore_supported [gdb_gcore_cmd "$gcore_name" "saving gcore"]
>>>> +
>>>> + if {!$gcore_supported} {
>>>> + unsupported "couldn't generate gcore file"
>>>> + return
>>>> + }
>>>> +
>>>> + set corefile [gdb_remote_download host $gcore_name]
>>>> +
>>>> + gdb_test "core-file $corefile" \
>>>> + "" \
>>>> + "loading_corefile" \
>>>> + "A program is being debugged already\\\. Kill it\\\? \\\(y or n\\\) " \
>>>> + "y"
>>>> +
>>>> + do_full_test
>>>> +}
>>>> +
>>>> +standard_testfile
>>>> +
>>>> +if [prepare_for_testing "failed to prepare" $testfile $srcfile \
>>>> + {debug pthreads}] {
>>>> + return -1
>>>> +}
>>>> +
>>>> +clean_restart ${binfile}
>>>> +
>>>> +gdb_test_no_output "set backtrace limit unlimited"
>>>> +
>>>> +test_live_inferior
>>>> +
>>>> +test_corefile
>>>> +
>>>> +test_gcore
>>>
>>>
>>
>
Thanks for the patch.
I re-tested this on aarch64-linux, for native gdb/gdbserver and extended native gdbserver.
I'm getting full passes on my end. The code looks good to me.
Approved-By: Luis Machado <luis.machado@arm.com>
On 24/01/2024 13:35, Luis Machado wrote:
> Thanks for the patch.
>
> I re-tested this on aarch64-linux, for native gdb/gdbserver and extended native gdbserver.
>
> I'm getting full passes on my end. The code looks good to me.
>
> Approved-By: Luis Machado<luis.machado@arm.com>
>
Thank you! I've pushed this patch
new file mode 100644
@@ -0,0 +1,443 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2023 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <pthread.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <unistd.h>
+
+/* The delay that the main thread gives once all the worker threads have
+ reached the barrier before the main thread enters the function on which
+ GDB will have placed a breakpoint. */
+
+#define MAIN_THREAD_DELAY 2
+
+/* The maximum time we allow this test program to run for before an alarm
+ signal is sent and everything will exit. */
+#define WATCHDOG_ALARM_TIME 600
+
+/* Aliases for the signals used within this script. Each signal
+ corresponds to an action (from the FINAL_ACTION enum) that the signal
+ handler will perform. */
+
+#define SPIN_SIGNAL SIGUSR1
+#define SYSCALL_SIGNAL SIGUSR2
+
+/* Describe the final action that a thread should perform. */
+
+enum final_action
+ {
+ /* Thread should spin in an infinite loop. */
+ SPIN = 0,
+
+ /* Thread should block in a syscall. */
+ SYSCALL,
+
+ /* This is just a marker to allow for looping over the enum. */
+ LAST_ACTION
+ };
+
+/* Where should the thread perform this action? */
+
+enum exec_location
+ {
+ /* Just a normal thread, on a normal stack. */
+ NORMAL = 0,
+
+ /* In a signal handler, but use the normal stack. */
+ SIGNAL_HANDLER,
+
+ /* In a signal handler using an alternative stack. */
+ SIGNAL_ALT_STACK,
+
+ /* This is just a marker to allow for looping over the enum. */
+ LAST_LOCACTION
+ };
+
+/* A descriptor for a single thread job. We create a new thread for each
+ job_description. */
+
+struct job_description
+{
+ /* What action should this thread perform. */
+ enum final_action action;
+
+ /* Where should the thread perform the action. */
+ enum exec_location location;
+
+ /* The actual thread handle, so we can join with the thread. */
+ pthread_t thread;
+};
+
+/* A pthread barrier, used to (try) and synchronise the threads. */
+pthread_barrier_t global_barrier;
+
+/* Return a list of jobs, and place the length of the list in *COUNT. */
+
+struct job_description *
+get_job_list (int *count)
+{
+ /* The number of jobs. */
+ int num = LAST_ACTION * LAST_LOCACTION;
+
+ /* The uninitialised array of jobs. */
+ struct job_description *list
+ = malloc (num * sizeof (struct job_description));
+ assert (list != NULL);
+
+ /* Fill the array with all possible jobs. */
+ for (int i = 0; i < (int) LAST_ACTION; ++i)
+ for (int j = 0; j < (int) LAST_LOCACTION; ++j)
+ {
+ int idx = (i * LAST_LOCACTION) + j;
+ list[idx].action = (enum final_action) i;
+ list[idx].location = (enum exec_location) j;
+ }
+
+ /* Return the array of jobs. */
+ *count = num;
+ return list;
+}
+
+/* This function should never be called. If it is then an assertion will
+ trigger. */
+
+void
+assert_not_reached (void)
+{
+ assert (0);
+}
+
+/* The function for a SPIN action. Just spins in a loop. The LOCATION
+ argument exists so GDB can identify the expected context for this
+ function. */
+
+void
+do_spin_task (enum exec_location location)
+{
+ (void) location;
+
+ /* Let everyone know that we're about to perform our action. */
+ int res = pthread_barrier_wait (&global_barrier);
+ assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
+
+ while (1)
+ {
+ /* Nothing. */
+ }
+}
+
+/* The function for a SYSCALL action. Just spins in a loop. The LOCATION
+ argument exists so GDB can identify the expected context for this
+ function. */
+
+void
+do_syscall_task (enum exec_location location)
+{
+ (void) location;
+
+ /* Let everyone know that we're about to perform our action. */
+ int res = pthread_barrier_wait (&global_barrier);
+ assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
+
+ sleep (600);
+}
+
+/* Return the required size for a sigaltstack. We start with a single
+ page, but do check against the system defined minimums. We don't run
+ much on the alternative stacks, so we don't need a huge one. */
+
+size_t
+get_stack_size (void)
+{
+ size_t size = getpagesize (); /* Arbitrary starting size. */
+ if (size < SIGSTKSZ)
+ size = SIGSTKSZ;
+ if (size < MINSIGSTKSZ)
+ size = MINSIGSTKSZ;
+ return size;
+}
+
+/* A descriptor for an alternative stack. */
+
+struct stack_descriptor
+{
+ /* The base address of the alternative stack. This is the address that
+ must be freed to release the memory used by this stack. */
+ void *base;
+
+ /* The size of this alternative stack. Tracked just so we can query this
+ from GDB. */
+ size_t size;
+};
+
+/* Install an alternative signal stack. Return a descriptor for the newly
+ allocated alternative stack. */
+
+struct stack_descriptor
+setup_alt_stack (void)
+{
+ size_t stack_size = get_stack_size ();
+
+ void *stack_area = malloc (stack_size);
+
+ stack_t stk;
+ stk.ss_sp = stack_area;
+ stk.ss_flags = 0;
+ stk.ss_size = stack_size;
+
+ int res = sigaltstack (&stk, NULL);
+ assert (res == 0);
+
+ struct stack_descriptor desc;
+ desc.base = stack_area;
+ desc.size = stack_size;
+
+ return desc;
+}
+
+/* Return true (non-zero) if we are currently on the alternative stack,
+ otherwise, return false (zero). */
+
+int
+on_alt_stack_p (void)
+{
+ stack_t stk;
+ int res = sigaltstack (NULL, &stk);
+ assert (res == 0);
+
+ return (stk.ss_flags & SS_ONSTACK) != 0;
+}
+
+/* The signal handler function. All signals call here, so we use SIGNO
+ (the signal that was delivered) to decide what action to perform. This
+ function might, or might not, have been called on an alternative signal
+ stack. */
+
+void
+signal_handler (int signo)
+{
+ enum exec_location location
+ = on_alt_stack_p () ? SIGNAL_ALT_STACK : SIGNAL_HANDLER;
+
+ switch (signo)
+ {
+ case SPIN_SIGNAL:
+ do_spin_task (location);
+ break;
+
+ case SYSCALL_SIGNAL:
+ do_syscall_task (location);
+ break;
+
+ default:
+ assert_not_reached ();
+ }
+}
+
+/* The thread worker function. ARG is a job_description pointer which
+ describes what this thread is expected to do. This function always
+ returns a NULL pointer. */
+
+void *
+thread_function (void *arg)
+{
+ struct job_description *job = (struct job_description *) arg;
+ struct stack_descriptor desc = { NULL, 0 };
+ int sa_flags = 0;
+
+ switch (job->location)
+ {
+ case NORMAL:
+ /* This thread performs the worker action on the current thread,
+ select the correct worker function based on the requested
+ action. */
+ switch (job->action)
+ {
+ case SPIN:
+ do_spin_task (NORMAL);
+ break;
+
+ case SYSCALL:
+ do_syscall_task (NORMAL);
+ break;
+
+ default:
+ assert_not_reached ();
+ }
+ break;
+
+ case SIGNAL_ALT_STACK:
+ /* This thread is to perform its action in a signal handler on the
+ alternative stack. Install the alternative stack now, and then
+ fall through to the normal signal handler location code. */
+ desc = setup_alt_stack ();
+ assert (desc.base != NULL);
+ assert (desc.size > 0);
+ sa_flags = SA_ONSTACK;
+
+ /* Fall through. */
+ case SIGNAL_HANDLER:
+ {
+ /* This thread is to perform its action in a signal handler. We
+ might have just installed an alternative signal stack. */
+ int signo, res;
+
+ /* Select the correct signal number so that the signal handler will
+ perform the required action. */
+ switch (job->action)
+ {
+ case SPIN:
+ signo = SPIN_SIGNAL;
+ break;
+
+ case SYSCALL:
+ signo = SYSCALL_SIGNAL;
+ break;
+
+ default:
+ assert_not_reached ();
+ }
+
+ /* Now setup the signal handler. */
+ struct sigaction sa;
+ sa.sa_handler = signal_handler;
+ sigfillset (&sa.sa_mask);
+ sa.sa_flags = sa_flags;
+ res = sigaction (signo, &sa, NULL);
+ assert (res == 0);
+
+ /* Send the signal to this thread. */
+ res = pthread_kill (job->thread, signo);
+ assert (res == 0);
+ }
+ break;
+
+ default:
+ assert_not_reached ();
+ };
+
+ /* Free the alt-stack if we allocated one, if not DESC.BASE will be
+ NULL so this call is fine. */
+ free (desc.base);
+
+ /* Thread complete. */
+ return NULL;
+}
+
+void
+start_job (struct job_description *job)
+{
+ int res;
+
+ res = pthread_create (&job->thread, NULL, thread_function, job);
+ assert (res == 0);
+}
+
+/* Join with the thread for JOB. This will block until the thread for JOB
+ has finished. */
+
+void
+finalise_job (struct job_description *job)
+{
+ int res;
+ void *retval;
+
+ res = pthread_join (job->thread, &retval);
+ assert (res == 0);
+ assert (retval == NULL);
+}
+
+/* Function that GDB can place a breakpoint on. */
+
+void
+breakpt (void)
+{
+ /* Nothing. */
+}
+
+/* Function that triggers a crash, if the user has setup their environment
+ correctly this will dump a core file, which GDB can then examine. */
+
+void
+crash_function (void)
+{
+ volatile int *p = 0;
+ volatile int n = *p;
+ (void) n;
+}
+
+/* Entry point. */
+
+int
+main ()
+{
+ int job_count, res;
+ struct job_description *jobs = get_job_list (&job_count);
+
+ /* This test is going to park some threads inside infinite loops. Just
+ in case this program is left running, install an alarm that will cause
+ everything to exit. */
+ alarm (WATCHDOG_ALARM_TIME);
+
+ /* We want each worker thread (of which there are JOB_COUNT) plus the
+ main thread (hence + 1) to wait at the barrier. */
+ res = pthread_barrier_init (&global_barrier, NULL, job_count + 1);
+ assert (res == 0);
+
+ /* Start all the jobs. */
+ for (int i = 0; i < job_count; ++i)
+ start_job (&jobs[i]);
+
+ /* Notify all the worker threads that we're waiting for them. */
+ res = pthread_barrier_wait (&global_barrier);
+ assert (res == PTHREAD_BARRIER_SERIAL_THREAD || res == 0);
+
+ /* All we know at this point is that all the worker threads have reached
+ the barrier, which is just before they perform their action. But we
+ really want them to start their action.
+
+ There's really no way we can be 100% certain that the worker threads
+ have started their action, all we can do is wait for a short while and
+ hope that the machine we're running on is not too slow. */
+ sleep (MAIN_THREAD_DELAY);
+
+ /* A function that GDB can place a breakpoint on. By the time we get
+ here we are as sure as we can be that all of the worker threads have
+ started and are in their worker action (spinning, or syscall). */
+ breakpt ();
+
+ /* If GDB is not attached then this function will cause a crash, which
+ can be used to dump a core file, which GDB can then analyse. */
+ crash_function ();
+
+ /* Due to the crash we never expect to get here. Plus the worker actions
+ never terminate. But for completeness, here's where we join with all
+ the worker threads. */
+ for (int i = 0; i < job_count; ++i)
+ finalise_job (&jobs[i]);
+
+ /* Cleanup the barrier. */
+ res = pthread_barrier_destroy (&global_barrier);
+ assert (res == 0);
+
+ /* And clean up the jobs list. */
+ free (jobs);
+
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,233 @@
+# This testcase is part of GDB, the GNU debugger.
+
+# Copyright 2023 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This test case looks at GDB's ability to get correct backtraces for a
+# crashed inferior, recreating it from a live inferior, a corefile and
+# a gcore.
+
+
+# Check that the inferior has 7 threads, and return the number of threads (7).
+# We return the thread count so that, even if there is some error in the test,
+# the final log doesn't get flooded with failures.
+
+proc test_thread_count {} {
+ set thread_count 0
+
+ gdb_test_multiple "info threads" "getting thread count" -lbl {
+ -re "Thread" {
+ incr thread_count
+ exp_continue
+ }
+ -re "$::gdb_prompt " {
+ gdb_assert {$thread_count == 7}
+ }
+ }
+
+ return $thread_count
+}
+
+# Use 'thread apply all backtrace' to check if all expected threads
+# are present, and stopped in the expected locations. Set the global
+# TEST_LIST to be the a list of regexps expected to match all the
+# threads. We generate it now so that the list is in the order that
+# GDB sees the threads.
+
+proc thread_apply_all {} {
+ global test_list
+
+ set test_list { }
+
+ set unwind_fail false
+
+ gdb_test_multiple "thread apply all backtrace" \
+ "Get thread information" -lbl {
+ -re "#\[0-9\]+\\\?\\\?\[^\n\]*" {
+ set unwind_fail true
+ exp_continue
+ }
+ -re "\[^\n\]*syscall_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
+ lappend test_list [multi_line ".*sleep.*" \
+ ".*do_syscall_task .location=SIGNAL_ALT_STACK.*" \
+ ".*signal_handler.*" \
+ ".*signal handler called.*" \
+ ".*pthread_kill.*" \
+ ".*thread_function.*"]
+ exp_continue
+ }
+ -re "\[^\n\]*syscall_task .location=SIGNAL_HANDLER\[^\n\]*" {
+ lappend test_list [multi_line ".*sleep.*" \
+ ".*do_syscall_task .location=SIGNAL_HANDLER.*" \
+ ".*signal_handler.*" \
+ ".*signal handler called.*" \
+ ".*pthread_kill.*" \
+ ".*thread_function.*"]
+ exp_continue
+ }
+ -re "\[^\n\]*syscall_task .location=NORMAL\[^\n\]*" {
+ lappend test_list [multi_line ".*sleep.*" \
+ ".*do_syscall_task .location=NORMAL.*" \
+ ".*thread_function.*"]
+ exp_continue
+ }
+ -re "\[^\n\]*spin_task .location=SIGNAL_ALT_STACK\[^\n\]*" {
+ lappend test_list [multi_line ".*do_spin_task .location=SIGNAL_ALT_STACK.*" \
+ ".*signal_handler.*" \
+ ".*signal handler called.*" \
+ ".*pthread_kill.*" \
+ ".*thread_function.*"]
+ exp_continue
+ }
+ -re "\[^\n\]*spin_task .location=SIGNAL_HANDLER\[^\n\]*" {
+ lappend test_list [multi_line ".*do_spin_task .location=SIGNAL_HANDLER.*" \
+ ".*signal_handler.*" \
+ ".*signal handler called.*" \
+ ".*pthread_kill.*" \
+ ".*thread_function.*"]
+ exp_continue
+ }
+ -re "\[^\n\]*spin_task .location=NORMAL\[^\n\]*" {
+ lappend test_list [multi_line ".*do_spin_task .location=NORMAL..*" \
+ ".*thread_function.*"]
+ exp_continue
+ }
+ -re "\[^\n\]*main\[^\n\]*" {
+ lappend test_list ".*main.*"
+ exp_continue
+ }
+ -re "$::gdb_prompt " {
+ pass $gdb_test_name
+ }
+ }
+
+ gdb_assert {$unwind_fail == false}
+}
+
+# Perform all the tests we're interested in. They are:
+# * test if we have 7 threads
+# * Creating the list of backtraces for all threads seen
+# * testing if GDB recreated the full backtrace we expect for all threads
+
+proc do_full_test {} {
+ global test_list
+ set thread_count [test_thread_count]
+
+ thread_apply_all
+
+ gdb_assert {$thread_count == [llength $test_list]}
+
+ for {set i 0} {$i < $thread_count } {incr i} {
+ set thread_num [expr [llength $test_list] - $i]
+
+ gdb_test "thread apply $thread_num backtrace" [lindex $test_list $i]
+ }
+}
+
+# Do all preparation steps for running the corefile tests, then
+# call do_full_test to actually run the tests.
+
+proc_with_prefix test_live_inferior {} {
+ gdb_test "handle SIGUSR1 nostop print pass" \
+ ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
+ "setup SIGUSR1"
+ gdb_test "handle SIGUSR2 nostop print pass" \
+ ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
+ "setup SIGUSR2"
+
+ if {![runto_main]} {
+ return
+ }
+
+ gdb_breakpoint "breakpt"
+ gdb_continue_to_breakpoint "running to breakpoint" ".*"
+
+ do_full_test
+}
+
+# Do all preparation steps for running the corefile tests, then
+# call do_full_test to actually run the tests.
+
+proc_with_prefix test_corefile {} {
+ set corefile [core_find $::binfile]
+ if { $corefile == "" } {
+ untested "couldn't generate corefile"
+ return
+ }
+ set corefile [gdb_remote_download host $corefile]
+
+ gdb_test "core-file $corefile" \
+ "" \
+ "loading_corefile" \
+ "A program is being debugged already\\\. Kill it\\\? \\\(y or n\\\) " \
+ "y"
+
+ do_full_test
+}
+
+# Do all preparation steps for running the gcore tests, then
+# call do_full_test to actually run the tests.
+
+proc_with_prefix test_gcore {} {
+
+ clean_restart "$::binfile"
+
+ gdb_test "handle SIGUSR1 nostop print pass" \
+ ".*SIGUSR1.*No.*Yes.*Yes.*User defined signal 1" \
+ "setup SIGUSR1"
+ gdb_test "handle SIGUSR2 nostop print pass" \
+ ".*SIGUSR2.*No.*Yes.*Yes.*User defined signal 2" \
+ "setup SIGUSR2"
+
+ if {![runto_main]} {
+ return -1
+ }
+ gdb_test "continue" ".*Segmentation fault.*" "continue to crash"
+
+ set gcore_name "${::binfile}.gcore"
+ set gcore_supported [gdb_gcore_cmd "$gcore_name" "saving gcore"]
+
+ if {!$gcore_supported} {
+ unsupported "couldn't generate gcore file"
+ return
+ }
+
+ set corefile [gdb_remote_download host $gcore_name]
+
+ gdb_test "core-file $corefile" \
+ "" \
+ "loading_corefile" \
+ "A program is being debugged already\\\. Kill it\\\? \\\(y or n\\\) " \
+ "y"
+
+ do_full_test
+}
+
+standard_testfile
+
+if [prepare_for_testing "failed to prepare" $testfile $srcfile \
+ {debug pthreads}] {
+ return -1
+}
+
+clean_restart ${binfile}
+
+gdb_test_no_output "set backtrace limit unlimited"
+
+test_live_inferior
+
+test_corefile
+
+test_gcore