95e50b2723
This fixes invalid reads Valgrind first caught when debugging against a GDBserver patched with a series that adds exec events to the remote protocol. Like these, using the gdb.threads/thread-execl.exp test: $ valgrind ./gdb -data-directory=data-directory ./testsuite/gdb.threads/thread-execl -ex "tar extended-remote :9999" -ex "b thread_execler" -ex "c" -ex "set scheduler-locking on" ... Breakpoint 1, thread_execler (arg=0x0) at src/gdb/testsuite/gdb.threads/thread-execl.c:29 29 if (execl (image, image, NULL) == -1) (gdb) n Thread 32509.32509 is executing new program: build/gdb/testsuite/gdb.threads/thread-execl [New Thread 32509.32532] ==32510== Invalid read of size 4 ==32510== at 0x5AA7D8: delete_breakpoint (breakpoint.c:13989) ==32510== by 0x6285D3: delete_thread_breakpoint (thread.c:100) ==32510== by 0x628603: delete_step_resume_breakpoint (thread.c:109) ==32510== by 0x61622B: delete_thread_infrun_breakpoints (infrun.c:2928) ==32510== by 0x6162EF: for_each_just_stopped_thread (infrun.c:2958) ==32510== by 0x616311: delete_just_stopped_threads_infrun_breakpoints (infrun.c:2969) ==32510== by 0x616C96: fetch_inferior_event (infrun.c:3267) ==32510== by 0x63A2DE: inferior_event_handler (inf-loop.c:57) ==32510== by 0x4E0E56: remote_async_serial_handler (remote.c:11877) ==32510== by 0x4AF620: run_async_handler_and_reschedule (ser-base.c:137) ==32510== by 0x4AF6F0: fd_event (ser-base.c:182) ==32510== by 0x63806D: handle_file_event (event-loop.c:762) ==32510== Address 0xcf333e0 is 16 bytes inside a block of size 200 free'd ==32510== at 0x4A07577: free (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so) ==32510== by 0x77CB74: xfree (common-utils.c:98) ==32510== by 0x5AA954: delete_breakpoint (breakpoint.c:14056) ==32510== by 0x5988BD: update_breakpoints_after_exec (breakpoint.c:3765) ==32510== by 0x61360F: follow_exec (infrun.c:1091) ==32510== by 0x6186FA: handle_inferior_event (infrun.c:4061) ==32510== by 0x616C55: fetch_inferior_event (infrun.c:3261) ==32510== by 0x63A2DE: inferior_event_handler (inf-loop.c:57) ==32510== by 0x4E0E56: remote_async_serial_handler (remote.c:11877) ==32510== by 0x4AF620: run_async_handler_and_reschedule (ser-base.c:137) ==32510== by 0x4AF6F0: fd_event (ser-base.c:182) ==32510== by 0x63806D: handle_file_event (event-loop.c:762) ==32510== [Switching to Thread 32509.32532] Breakpoint 1, thread_execler (arg=0x0) at src/gdb/testsuite/gdb.threads/thread-execl.c:29 29 if (execl (image, image, NULL) == -1) (gdb) The breakpoint in question is the step-resume breakpoint of the non-main thread, the one that was "next"ed. The exact same issue can be seen on mainline with native debugging, by running the thread-execl.exp test in non-stop mode, because the kernel doesn't report a thread exit event for the execing thread. Tested on x86_64 Fedora 20. gdb/ChangeLog: 2015-03-02 Pedro Alves <palves@redhat.com> * infrun.c (follow_exec): Delete all threads of the process except the event thread. Extended comments. gdb/testsuite/ChangeLog: 2015-03-02 Pedro Alves <palves@redhat.com> * gdb.threads/thread-execl.exp (do_test): Handle non-stop. (top level): Call do_test with non-stop as well.
78 lines
2.2 KiB
Text
78 lines
2.2 KiB
Text
# Copyright (C) 2009-2015 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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#
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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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#
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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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# Test that GDB doesn't get stuck when stepping over an exec call done
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# by a thread other than the main thread.
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# There's no support for exec events in the remote protocol.
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if { [is_remote target] } {
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return 0
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}
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standard_testfile
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if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" \
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executable debug] != "" } {
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return -1
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}
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# Run the test proper. SCHEDLOCK specifies what scheduler-locking
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# should be set to.
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proc do_test { schedlock } {
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global binfile
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if {$schedlock == "non-stop"} {
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set prefix $schedlock
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} else {
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set prefix "schedlock $schedlock"
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}
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with_test_prefix "$prefix" {
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clean_restart ${binfile}
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if {$schedlock == "non-stop"} {
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gdb_test_no_output "set non-stop 1"
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}
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if ![runto_main] {
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return 0
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}
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# Get ourselves to the thread that execs.
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gdb_breakpoint "thread_execler"
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gdb_test "continue" ".*thread_execler.*" "continue to thread start"
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if {$schedlock == "non-stop"} {
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gdb_test "thread 2" \
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"Switching to .*thread_execler.*" \
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"switch to event thread"
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}
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# Now set a breakpoint at `main', and step over the execl call. The
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# breakpoint at main should be reached. GDB should not try to revert
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# back to the old thread from the old image and resume stepping it
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# (since it is gone).
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gdb_breakpoint "main"
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if {$schedlock != "non-stop"} {
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gdb_test_no_output "set scheduler-locking $schedlock"
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}
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gdb_test "next" ".*main.*" "get to main in new image"
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}
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}
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foreach schedlock {"off" "step" "on" "non-stop"} {
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do_test $schedlock
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}
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