From patchwork Fri Feb 7 12:04:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Aktemur, Tankut Baris" X-Patchwork-Id: 37725 Received: (qmail 121621 invoked by alias); 7 Feb 2020 12:04:36 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 121494 invoked by uid 89); 7 Feb 2020 12:04:35 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-22.4 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT autolearn=ham version=3.3.1 spammy=forever, 25478, Receiving, Connection X-HELO: mga17.intel.com Received: from mga17.intel.com (HELO mga17.intel.com) (192.55.52.151) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 07 Feb 2020 12:04:31 +0000 Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Feb 2020 04:04:30 -0800 Received: from irvmail001.ir.intel.com ([163.33.26.43]) by orsmga008.jf.intel.com with ESMTP; 07 Feb 2020 04:04:28 -0800 Received: from ulvlx001.iul.intel.com (ulvlx001.iul.intel.com [172.28.207.17]) by irvmail001.ir.intel.com (8.14.3/8.13.6/MailSET/Hub) with ESMTP id 017C4Su2021930; Fri, 7 Feb 2020 12:04:28 GMT Received: from ulvlx001.iul.intel.com (localhost [127.0.0.1]) by ulvlx001.iul.intel.com with ESMTP id 017C4RnD006494; Fri, 7 Feb 2020 13:04:27 +0100 Received: (from taktemur@localhost) by ulvlx001.iul.intel.com with LOCAL id 017C4RgF006490; Fri, 7 Feb 2020 13:04:27 +0100 From: Tankut Baris Aktemur To: gdb-patches@sourceware.org Cc: palves@redhat.com, tdevries@suse.de Subject: [PATCH v4 2/2] gdb/infrun: handle already-exited threads when attempting to stop Date: Fri, 7 Feb 2020 13:04:12 +0100 Message-Id: <2aff425c4d358fe95f67c2898bd8f7cd578d5bcb.1581065751.git.tankut.baris.aktemur@intel.com> In-Reply-To: <9512ee17-66dc-3463-4735-b1907bca34c6@redhat.com> References: <9512ee17-66dc-3463-4735-b1907bca34c6@redhat.com> In-Reply-To: References: X-IsSubscribed: yes In stop_all_threads, GDB sends signals to other threads in an attempt to stop them. While in a typical scenario the expected wait status is TARGET_WAITKIND_STOPPED, it is possible that the thread GDB attempted to stop has already terminated. If so, a waitstatus other than TARGET_WAITKIND_STOPPED would be received. Handle this case appropriately. If a wait status that denotes thread termination is ignored, GDB goes into an infinite loop in stop_all_threads. E.g.: ~~~ $ gdb ./a.out (gdb) start ... (gdb) add-inferior -exec ./a.out ... (gdb) inferior 2 ... (gdb) start ... (gdb) set schedule-multiple on (gdb) set debug infrun 2 (gdb) continue Continuing. infrun: clear_proceed_status_thread (process 23419) infrun: clear_proceed_status_thread (process 23703) infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT) infrun: proceed: resuming process 23419 infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 23419] at 0x55555555514e infrun: infrun_async(1) infrun: prepare_to_wait infrun: proceed: resuming process 23703 infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 23703] at 0x55555555514e infrun: prepare_to_wait infrun: target_wait (-1.0.0, status) = infrun: 23703.23703.0 [process 23703], infrun: status->kind = exited, status = 0 infrun: handle_inferior_event status->kind = exited, status = 0 [Inferior 2 (process 23703) exited normally] infrun: stop_waiting infrun: stop_all_threads infrun: stop_all_threads, pass=0, iterations=0 infrun: process 23419 executing, need stop infrun: target_wait (-1.0.0, status) = infrun: 23419.23419.0 [process 23419], infrun: status->kind = exited, status = 0 infrun: stop_all_threads status->kind = exited, status = 0 process 23419 infrun: process 23419 executing, already stopping infrun: target_wait (-1.0.0, status) = infrun: -1.0.0 [process -1], infrun: status->kind = no-resumed infrun: stop_all_threads status->kind = no-resumed process -1 infrun: process 23419 executing, already stopping infrun: target_wait (-1.0.0, status) = infrun: -1.0.0 [process -1], infrun: status->kind = no-resumed infrun: stop_all_threads status->kind = no-resumed process -1 infrun: process 23419 executing, already stopping infrun: target_wait (-1.0.0, status) = infrun: -1.0.0 [process -1], infrun: status->kind = no-resumed infrun: stop_all_threads status->kind = no-resumed process -1 infrun: process 23419 executing, already stopping infrun: target_wait (-1.0.0, status) = infrun: -1.0.0 [process -1], infrun: status->kind = no-resumed infrun: stop_all_threads status->kind = no-resumed process -1 infrun: process 23419 executing, already stopping ~~~ And this polling goes on forever. This patch prevents the infinite looping behavior. For the same scenario above, we obtain the following behavior: ~~~ ... (gdb) continue Continuing. infrun: clear_proceed_status_thread (process 8564) infrun: clear_proceed_status_thread (process 8652) infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT) infrun: proceed: resuming process 8564 infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 8564] at 0x55555555514e infrun: infrun_async(1) infrun: prepare_to_wait infrun: proceed: resuming process 8652 infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 8652] at 0x55555555514e infrun: prepare_to_wait infrun: Found 2 inferiors, starting at #0 infrun: target_wait (-1.0.0, status) = infrun: 8564.8564.0 [process 8564], infrun: status->kind = exited, status = 0 infrun: handle_inferior_event status->kind = exited, status = 0 [Inferior 1 (process 8564) exited normally] infrun: stop_waiting infrun: stop_all_threads infrun: stop_all_threads, pass=0, iterations=0 infrun: process 8652 executing, need stop infrun: target_wait (-1.0.0, status) = infrun: 8652.8652.0 [process 8652], infrun: status->kind = exited, status = 0 infrun: stop_all_threads status->kind = exited, status = 0 process 8652 infrun: saving status status->kind = exited, status = 0 for 8652.8652.0 infrun: process 8652 not executing infrun: stop_all_threads, pass=1, iterations=1 infrun: process 8652 not executing infrun: stop_all_threads done (gdb) infrun: Using pending wait status status->kind = exited, status = 0 for process 8652. infrun: target_wait (-1.0.0, status) = infrun: 8652.8652.0 [process 8652], infrun: status->kind = exited, status = 0 infrun: handle_inferior_event status->kind = exited, status = 0 [Inferior 2 (process 8652) exited normally] infrun: stop_waiting info inferiors Num Description Connection Executable 1 a.out * 2 a.out (gdb) info threads No threads. (gdb) ~~~ gdb/ChangeLog: 2020-02-05 Tankut Baris Aktemur Tom de Vries PR threads/25478 * infrun.c (stop_all_threads): Do NOT ignore TARGET_WAITKIND_NO_RESUMED, TARGET_WAITKIND_THREAD_EXITED, TARGET_WAITKIND_EXITED, TARGET_WAITKIND_SIGNALLED wait statuses received from threads we attempt to stop. gdb/testsuite/ChangeLog: 2019-11-04 Tankut Baris Aktemur * gdb.multi/multi-exit.c: New file. * gdb.multi/multi-exit.exp: New file. * gdb.multi/multi-kill.c: New file. * gdb.multi/multi-kill.exp: New file. Change-Id: I7cec98f40283773b79255d998511da434e9cd408 --- gdb/infrun.c | 38 ++++++++++-- gdb/testsuite/gdb.multi/multi-exit.c | 22 +++++++ gdb/testsuite/gdb.multi/multi-exit.exp | 81 +++++++++++++++++++++++++ gdb/testsuite/gdb.multi/multi-kill.c | 34 +++++++++++ gdb/testsuite/gdb.multi/multi-kill.exp | 84 ++++++++++++++++++++++++++ 5 files changed, 254 insertions(+), 5 deletions(-) create mode 100644 gdb/testsuite/gdb.multi/multi-exit.c create mode 100644 gdb/testsuite/gdb.multi/multi-exit.exp create mode 100644 gdb/testsuite/gdb.multi/multi-kill.c create mode 100644 gdb/testsuite/gdb.multi/multi-kill.exp diff --git a/gdb/infrun.c b/gdb/infrun.c index 9224376d05e..58a6da9ec32 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -4799,9 +4799,14 @@ stop_all_threads (void) "infrun: %s not executing\n", target_pid_to_str (t->ptid).c_str ()); - /* The thread may be not executing, but still be - resumed with a pending status to process. */ - t->resumed = false; + if ((t->suspend.waitstatus.kind == TARGET_WAITKIND_SIGNALLED + || t->suspend.waitstatus.kind == TARGET_WAITKIND_EXITED) + && t->suspend.waitstatus_pending_p) + ; + else + /* The thread may be not executing, but still be + resumed with a pending status to process. */ + t->resumed = false; } } @@ -4829,8 +4834,31 @@ stop_all_threads (void) || event.ws.kind == TARGET_WAITKIND_EXITED || event.ws.kind == TARGET_WAITKIND_SIGNALLED) { - /* All resumed threads exited - or one thread/process exited/signalled. */ + /* Eventing target is null if there were no waitable + targets. */ + if (event.target != nullptr) + { + thread_info *t = find_thread_ptid (event.target, + event.ptid); + /* Check if this is the first time we see this thread. + Don't bother adding if it individually exited. */ + if (t == nullptr + && event.ws.kind != TARGET_WAITKIND_THREAD_EXITED) + t = add_thread (event.target, event.ptid); + + if (t != nullptr) + { + /* Set the threads as non-executing to avoid + another stop attempt on them. */ + mark_non_executing_threads (event.target, event.ptid, + event.ws); + save_waitstatus (t, &event.ws); + /* This was cleared in mark_non_executing_threads. + Set it so this pending event is considered by + do_target_wait. */ + t->resumed = true; + } + } } else { diff --git a/gdb/testsuite/gdb.multi/multi-exit.c b/gdb/testsuite/gdb.multi/multi-exit.c new file mode 100644 index 00000000000..f4825c8a7c1 --- /dev/null +++ b/gdb/testsuite/gdb.multi/multi-exit.c @@ -0,0 +1,22 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2020 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 . */ + +int +main () +{ + return 0; +} diff --git a/gdb/testsuite/gdb.multi/multi-exit.exp b/gdb/testsuite/gdb.multi/multi-exit.exp new file mode 100644 index 00000000000..959f0e8740a --- /dev/null +++ b/gdb/testsuite/gdb.multi/multi-exit.exp @@ -0,0 +1,81 @@ +# This testcase is part of GDB, the GNU debugger. + +# Copyright 2020 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 . + +# Test receiving TARGET_WAITKIND_EXITED events from multiple +# inferiors. In all stop-mode, upon receiving the exit event from one +# of the inferiors, GDB will try to stop the other inferior, too. So, +# a stop request will be sent. Receiving a TARGET_WAITKIND_EXITED +# status kind as a response to that stop request instead of a +# TARGET_WAITKIND_STOPPED should be handled by GDB without problems. + +standard_testfile + +# This is a test specific for native GDB's ability to stop all +# threads. +if {![can_spawn_for_attach]} { + return 0 +} + +if {[prepare_for_testing "failed to prepare" $testfile $srcfile]} { + return -1 +} + +gdb_test "add-inferior -exec $binfile" "Added inferior 2.*" \ + "add the second inferior" + +proc test {} { + # Start the processes separately. + gdb_test_no_output "set schedule-multiple off" + + gdb_test "inferior 1" ".*Switching to inferior 1.*" + if {![runto_main]} { + fail "starting inferior 1" + return -1 + } + + gdb_test "inferior 2" ".*Switching to inferior 2.*" + if {![runto_main]} { + fail "starting inferior 2" + return -1 + } + + # Now continue both processes. + gdb_test_no_output "set schedule-multiple on" + + # We want GDB to complete the command and return the prompt + # instead of going into an infinite loop. + # Both inferiors exit. + global inferior_exited_re gdb_prompt + set count 0 + gdb_test_multiple "continue" "continue" { + -re "$inferior_exited_re normally\]\[\r\n\]+" { + incr count + if {$count == 2} { + pass $gdb_test_name + } else { + exp_continue + } + } + -re "$gdb_prompt " { + exp_continue + } + } +} + +with_test_prefix "iteration 1" test +# Repeat to also test re-runnability. +with_test_prefix "iteration 2" test diff --git a/gdb/testsuite/gdb.multi/multi-kill.c b/gdb/testsuite/gdb.multi/multi-kill.c new file mode 100644 index 00000000000..3622c499202 --- /dev/null +++ b/gdb/testsuite/gdb.multi/multi-kill.c @@ -0,0 +1,34 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2020 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 . */ + +/* This program is intended to be started outside of gdb, and then + attached to by gdb. */ + +#include + +int +main () +{ + /* Don't run forever in case GDB crashes and DejaGNU fails to kill + this program. */ + alarm (10); + + while (1) + ; + + return 0; +} diff --git a/gdb/testsuite/gdb.multi/multi-kill.exp b/gdb/testsuite/gdb.multi/multi-kill.exp new file mode 100644 index 00000000000..6d509d9f0ba --- /dev/null +++ b/gdb/testsuite/gdb.multi/multi-kill.exp @@ -0,0 +1,84 @@ +# This testcase is part of GDB, the GNU debugger. + +# Copyright 2020 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 . + +# Test receiving TARGET_WAITKIND_SIGNALLED events from multiple +# inferiors. In all stop-mode, upon receiving the exit event from one +# of the inferiors, GDB will try to stop the other inferior, too. So, +# a stop request will be sent. Receiving a TARGET_WAITKIND_SIGNALLED +# status kind as a response to that stop request instead of a +# TARGET_WAITKIND_STOPPED should be handled by GDB without problems. + +standard_testfile + +# This is a test specific for native GDB's ability to stop all +# threads. +if {![can_spawn_for_attach]} { + return 0 +} + +if {[prepare_for_testing "failed to prepare" $testfile $srcfile]} { + return -1 +} + +gdb_test "add-inferior -exec $binfile" "Added inferior 2.*" \ + "add the second inferior" + +# We want both processes in a running state. +gdb_test_no_output "set schedule-multiple on" + +proc test {} { + # Start the programs, attach to them, then kill both from outside. + global binfile + global gdb_prompt + + set spawn_id_list [spawn_wait_for_attach [list $binfile $binfile]] + set test_spawn_id1 [lindex $spawn_id_list 0] + set test_spawn_id2 [lindex $spawn_id_list 1] + set testpid1 [spawn_id_get_pid $test_spawn_id1] + set testpid2 [spawn_id_get_pid $test_spawn_id2] + + gdb_test "inferior 1" ".*Switching to inferior 1.*" + + gdb_test "attach $testpid1" \ + "Attaching to program: .*, process $testpid1.*(in|at).*" \ + "attach to program 1" + + gdb_test "inferior 2" ".*Switching to inferior 2.*" + + gdb_test "attach $testpid2" \ + "Attaching to program: .*, process $testpid2.*(in|at).*" \ + "attach to program 2" + + gdb_test_multiple "continue" "continue processes" { + -re "Continuing.\[\r\n\]+" { + # Kill both processes at once. + remote_exec build "kill -9 ${testpid1} ${testpid2}" + exp_continue + } + -re "Program terminated with signal.*$gdb_prompt" { + pass $gdb_test_name + } + } + + # Make sure that the processes are gone. + kill_wait_spawned_process $test_spawn_id1 + kill_wait_spawned_process $test_spawn_id2 +} + +with_test_prefix "iteration 1" test +# Repeat to also test re-runnability. +with_test_prefix "iteration 2" test