f50bf8e515
This patch fixes a GDBserver crash when one thread is stepping over a syscall instruction which is exit. Step-over isn't finished due to the exit, but GDBserver doesn't clean up the state of step-over, so in the wait next time, GDBserver will wait on step_over_bkpt, which is already exited, and GDBserver crashes because 'requested_child' is NULL. See gdbserver logs below, Need step over [LWP 14858]? yes, found breakpoint at 0x2aaaaad91307^M proceed_all_lwps: found thread 14858 needing a step-over^M Starting step-over on LWP 14858. Stopping all threads^M >>>> entering void stop_all_lwps(int, lwp_info*) .... <<<< exiting void stop_all_lwps(int, lwp_info*)^M Done stopping all threads for step-over.^M pc is 0x2aaaaad91307^M Writing 0f to 0x2aaaaad91307 in process 14858^M Could not find fast tracepoint jump at 0x2aaaaad91307 in list (uninserting).^M pending reinsert at 0x2aaaaad91307^M step from pc 0x2aaaaad91307^M Resuming lwp 14858 (step, signal 0, stop not expected)^M # Start step-over for LWP 14858 >>>> entering ptid_t linux_wait_1(ptid_t, target_waitstatus*, int) .... LLFE: 14858 exited. ... <<<< exiting ptid_t linux_wait_1(ptid_t, target_waitstatus*, int) # LWP 14858 exited ..... >>>> entering ptid_t linux_wait_1(ptid_t, target_waitstatus*, int)^M linux_wait_1: [<all threads>]^M step_over_bkpt set [LWP 14858.14858], doing a blocking wait # but step_over_bkpt is still LWP 14858, which is wrong The fix is to finish step-over if it is ongoing, and unsuspend other threads. Without the fix in linux-low.c, GDBserver will crash in with running gdb.base/step-over-exit.exp. gdb/gdbserver: 2016-06-17 Yao Qi <yao.qi@linaro.org> * linux-low.c (unsuspend_all_lwps): Declare. (linux_low_filter_event): If thread exited, call finish_step_over. If step-over is finished, unsuspend other threads. gdb/testsuite: 2016-06-17 Yao Qi <yao.qi@linaro.org> * gdb.base/step-over-exit.c: New. * gdb.base/step-over-exit.exp: New.
50 lines
1.1 KiB
C
50 lines
1.1 KiB
C
/* This testcase is part of GDB, the GNU debugger.
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Copyright 2016 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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static void
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marker (void)
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{}
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int
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main (void)
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{
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int pid;
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pid = fork ();
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if (pid == 0) /* child */
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{
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_exit (0);
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}
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else
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{
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}
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pid = fork ();
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if (pid == 0) /* child */
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{
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marker ();
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_exit (0);
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}
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else
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{
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marker ();
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}
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}
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