Fix 'gcore' with exited threads
Commit Message
Hi,
https://bugzilla.redhat.com/show_bug.cgi?id=1099405
Program received signal SIGABRT, Aborted.
[...]
(gdb) gcore foobar
Couldn't get registers: No such process.
(gdb) info threads
[...]
(gdb) gcore foobar
Saved corefile foobar
(gdb)
gcore tries to access the exited thread:
[Thread 0x7ffff7fce700 (LWP 6895) exited]
ptrace(PTRACE_GETREGS, 6895, 0, 0x7fff18167dd0) = -1 ESRCH (No such process)
Without the TRY_CATCH protection testsuite FAILs for:
FAIL: gdb.threads/gcore-thread.exp: save a zeroed-threads corefile
FAIL: gdb.threads/gcore-thread.exp: core0file: re-load generated corefile (bad file format)
Maybe the TRY_CATCH could be more inside update_thread_list().
Similar update_thread_list() call is IMO missing in procfs_make_note_section()
but I do not have where to verify that change.
Jan
gdb/
2014-06-09 Jan Kratochvil <jan.kratochvil@redhat.com>
* linux-tdep.c (linux_make_corefile_notes): call update_thread_list,
protected against exceptions.
gdb/testsuite/
2014-06-09 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.threads/gcore-stale-thread.c: New file.
* gdb.threads/gcore-stale-thread.exp: New file.
Comments
On 06/09/2014 09:30 PM, Jan Kratochvil wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1099405
>
> Program received signal SIGABRT, Aborted.
> [...]
> (gdb) gcore foobar
> Couldn't get registers: No such process.
> (gdb) info threads
> [...]
> (gdb) gcore foobar
> Saved corefile foobar
> (gdb)
>
> gcore tries to access the exited thread:
> [Thread 0x7ffff7fce700 (LWP 6895) exited]
> ptrace(PTRACE_GETREGS, 6895, 0, 0x7fff18167dd0) = -1 ESRCH (No such process)
Note this will still happen if you have the exited thread selected,
as in that case the thread can't be deleted:
$ ./gdb ~/gdb/tests/threads -ex "set non-stop on"
...
(gdb) t 2
[Switching to thread 2 (Thread 0x7ffff7fc6700 (LWP 23009))]
#0 thread_function0 (arg=0x0) at threads.c:64
64 usleep (1); /* Loop increment. */
(gdb) p *myp=0
$1 = 0
(gdb) c&
Continuing.
(gdb) [Thread 0x7ffff7fc6700 (LWP 23009) exited]
(gdb) thread
[Current thread is 2 (Thread 0x7ffff7fc6700 (LWP 22973)) (exited)]
(gdb) info threads
Id Target Id Frame
3 Thread 0x7ffff77c5700 (LWP 22974) "threads" (running)
1 Thread 0x7ffff7fc7740 (LWP 22972) "threads" (running)
The current thread <Thread ID 2> has terminated. See `help thread'.
(gdb) gcore
Couldn't get registers: No such process.
(gdb)
It seems to me linux_corefile_thread_callback should skip exited
threads too.
> Without the TRY_CATCH protection testsuite FAILs for:
> FAIL: gdb.threads/gcore-thread.exp: save a zeroed-threads corefile
> FAIL: gdb.threads/gcore-thread.exp: core0file: re-load generated corefile (bad file format)
What does the log show ?
> Maybe the TRY_CATCH could be more inside update_thread_list().
I'll assume "info threads" is failing at that point too
then. Maybe we should downgrade whatever error is triggering
to a warning?
> Similar update_thread_list() call is IMO missing in procfs_make_note_section()
> but I do not have where to verify that change.
I wonder whether we should update the thread list in generic
code (write_gcore_file).
> +gdb_test_multiple "help gcore" "help gcore" {
> + -re "Undefined command: .gcore.*\r\n$gdb_prompt $" {
Is this coming from copy/paste of existing tests? I believe
this is is stale -- gcore.o has been in COMMON_OBS for a while
now. I think the actual error will be whatever the default for
the target method throws.
> + # gcore command not supported -- nothing to test here.
> + unsupported "gdb does not support gcore on this target"
> + return -1
> + }
> + -re "Save a core file .*\r\n$gdb_prompt $" {
> + pass "help gcore"
> + }
> +}
@@ -1440,6 +1440,7 @@ linux_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size,
char *note_data = NULL;
gdb_byte *auxv;
int auxv_len;
+ volatile struct gdb_exception e;
if (linux_fill_prpsinfo (&prpsinfo))
{
@@ -1463,6 +1464,12 @@ linux_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size,
}
/* Thread register information. */
+ TRY_CATCH (e, RETURN_MASK_ERROR)
+ {
+ update_thread_list ();
+ }
+ if (e.reason < 0)
+ exception_print (gdb_stderr, e);
thread_args.gdbarch = gdbarch;
thread_args.pid = ptid_get_pid (inferior_ptid);
thread_args.obfd = obfd;
new file mode 100644
@@ -0,0 +1,39 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2014 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>
+
+static void *
+start (void *arg)
+{
+ return arg;
+}
+
+int
+main (void)
+{
+ pthread_t thread;
+ int i;
+
+ i = pthread_create (&thread, NULL, start, NULL);
+ assert (i == 0);
+ i = pthread_join (thread, NULL);
+ assert (i == 0);
+
+ return 0; /* break-here */
+}
new file mode 100644
@@ -0,0 +1,56 @@
+# Copyright 2014 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 file was written by Michael Snyder (msnyder@redhat.com)
+# This is a test for the gdb command "generate-core-file".
+
+standard_testfile
+set corefile [standard_output_file ${testfile}.core]
+
+if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable debug] != ""} {
+ return -1
+}
+
+clean_restart ${testfile}
+
+gdb_test_multiple "help gcore" "help gcore" {
+ -re "Undefined command: .gcore.*\r\n$gdb_prompt $" {
+ # gcore command not supported -- nothing to test here.
+ unsupported "gdb does not support gcore on this target"
+ return -1
+ }
+ -re "Save a core file .*\r\n$gdb_prompt $" {
+ pass "help gcore"
+ }
+}
+
+if { ! [ runto_main ] } then {
+ return -1
+}
+
+gdb_test_multiple "info threads" "threads are supported" {
+ -re ".* main .*\r\n$gdb_prompt $" {
+ # OK, threads are supported.
+ }
+ -re "\r\n$gdb_prompt $" {
+ unsupported "gdb does not support threads on this target"
+ return -1
+ }
+}
+
+gdb_breakpoint ${srcfile}:[gdb_get_line_number "break-here"]
+gdb_continue_to_breakpoint "break-here" ".* break-here .*"
+
+gdb_gcore_cmd "$corefile" "save a corefile"