From c29705b71a8ec966478c0dc4712194a95291c6de Mon Sep 17 00:00:00 2001 From: Philippe Waroquiers Date: Sun, 24 Mar 2019 15:14:55 +0100 Subject: [PATCH] Fix internal error and improve 'set debug infrun 1'/target wait kind trace The test gdb.threads/watchthreads-reorder.exp verifies that the 'set debug infrun 1' debug output does not crash GDB. Under high load, the test can still cause a GDB internal error (see details below). This patch fixes this crash, and improves/factorises some wait kind traces. Tested on debian/amd64 + run one test with 'set debug infrun 1'. Changes compared to the first version: * Handles the suggestions of Kevin to trace the relevant elements of the wait status (this is done by calling target_waitstatus_to_string). * Some other changes to factorise wait status tracing. Note that using target_waitstatus_to_string instead of the 'locally printed' status kind strings means that debug trace that was using strings such as: "EXITED" or "TARGET_WAITKIND_EXITED" will now use what is printed by target_waitstatus_to_string e.g. "exited". gdb/ChangeLog 2019-04-01 Philippe Waroquiers * infrun.c (stop_all_threads): If debug_infrun, always trace the wait status after wait_one, using target_waitstatus_to_string and target_pid_to_str. (handle_inferior_event): Replace various trace of wait status kind by a single trace. * gdb/gnu-nat.c (gnu_nat_target::wait): Replace local wait status kind image by target_waitstatus_to_string. * target/waitstatus.c (target_waitstatus_to_string): Fix obsolete comment. (top-gdb) bt #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51 #1 0x00007f3d54a0642a in __GI_abort () at abort.c:89 #2 0x0000555c24c60e66 in dump_core () at ../../fixleaks/gdb/utils.c:201 #3 0x0000555c24c63d49 in internal_vproblem(internal_problem *, const char *, int, const char *, typedef __va_list_tag __va_list_tag *) (problem=problem@entry=0x555c25338d40 , file=, line=287, fmt=, ap=) at ../../fixleaks/gdb/utils.c:411 #4 0x0000555c24c63eab in internal_verror (file=, line=, fmt=, ap=) at ../../fixleaks/gdb/utils.c:436 #5 0x0000555c249e8c22 in internal_error (file=file@entry=0x555c24e0f2ad "../../fixleaks/gdb/inferior.c", line=line@entry=287, fmt=) at ../../fixleaks/gdb/common/errors.c:55 #6 0x0000555c247d3f5c in find_inferior_pid (pid=) at ../../fixleaks/gdb/inferior.c:287 #7 0x0000555c24ad2248 in find_inferior_pid (pid=) at ../../fixleaks/gdb/inferior.c:302 #8 find_inferior_ptid (ptid=...) at ../../fixleaks/gdb/inferior.c:301 #9 0x0000555c24c35f25 in find_thread_ptid (ptid=...) at ../../fixleaks/gdb/thread.c:522 #10 0x0000555c24b0ab4d in thread_db_target::pid_to_str[abi:cxx11](ptid_t) ( this=0x555c2532e3e0 , ptid=...) at ../../fixleaks/gdb/linux-thread-db.c:1637 #11 0x0000555c24c2f420 in target_pid_to_str[abi:cxx11](ptid_t) (ptid=...) at ../../fixleaks/gdb/target.c:2083 #12 0x0000555c24ad9cab in stop_all_threads () at ../../fixleaks/gdb/infrun.c:4373 #13 0x0000555c24ada00f in stop_waiting (ecs=) at ../../fixleaks/gdb/infrun.c:7464 #14 0x0000555c24adc401 in process_event_stop_test (ecs=ecs@entry=0x7ffc9402d9d0) at ../../fixleaks/gdb/infrun.c:6181 ... (top-gdb) fr 12 #12 0x0000555c24ad9cab in stop_all_threads () at ../../fixleaks/gdb/infrun.c:4373 (top-gdb) p event_ptid $5 = {m_pid = 25419, m_lwp = 25427, m_tid = 0} (top-gdb) p ptid $6 = {m_pid = 0, m_lwp = 0, m_tid = 0} (top-gdb) p ws $7 = {kind = TARGET_WAITKIND_THREAD_EXITED, value = {integer = 0, sig = GDB_SIGNAL_0, related_pid = {m_pid = 0, m_lwp = 0, m_tid = 0}, execd_pathname = 0x0, syscall_number = 0}} (top-gdb) The gdb.log corresponding to the above crash is: (gdb) PASS: gdb.threads/watchthreads-reorder.exp: reorder1: set debug infrun 1 continue Continuing. infrun: clear_proceed_status_thread (Thread 0x7ffff7fcfb40 (LWP 25419)) infrun: clear_proceed_status_thread (Thread 0x7ffff7310700 (LWP 25427)) infrun: clear_proceed_status_thread (Thread 0x7ffff6b0f700 (LWP 25428)) infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT) infrun: proceed: resuming Thread 0x7ffff7fcfb40 (LWP 25419) infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 0x7ffff7fcfb40 (LWP 25419)] at 0x7ffff7344317 infrun: infrun_async(1) infrun: prepare_to_wait infrun: proceed: resuming Thread 0x7ffff7310700 (LWP 25427) infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 0x7ffff7310700 (LWP 25427)] at 0x5555555553d7 infrun: prepare_to_wait infrun: proceed: resuming Thread 0x7ffff6b0f700 (LWP 25428) infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 0x7ffff6b0f700 (LWP 25428)] at 0x5555555554c8 infrun: prepare_to_wait infrun: target_wait (-1.0.0, status) = infrun: -1.0.0 [process -1], infrun: status->kind = ignore infrun: TARGET_WAITKIND_IGNORE infrun: prepare_to_wait Joining the threads. [Thread 0x7ffff6b0f700 (LWP 25428) exited] infrun: target_wait (-1.0.0, status) = infrun: -1.0.0 [process -1], infrun: status->kind = ignore infrun: TARGET_WAITKIND_IGNORE infrun: prepare_to_wait infrun: target_wait (-1.0.0, status) = infrun: 25419.25419.0 [Thread 0x7ffff7fcfb40 (LWP 25419)], infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP infrun: TARGET_WAITKIND_STOPPED infrun: stop_pc = 0x555555555e50 infrun: context switch infrun: Switching context from Thread 0x7ffff6b0f700 (LWP 25428) to Thread 0x7ffff7fcfb40 (LWP 25419) infrun: BPSTAT_WHAT_STOP_NOISY infrun: stop_waiting infrun: stop_all_threads infrun: stop_all_threads, pass=0, iterations=0 infrun: Thread 0x7ffff7fcfb40 (LWP 25419) not executing infrun: Thread 0x7ffff7310700 (LWP 25427) executing, need stop [Thread 0x7ffff7310700 (LWP 25427) exited] infrun: target_wait (-1.0.0, status) = infrun: 25419.25427.0 [LWP 25427], infrun: status->kind = thread exited, status = 0 infrun: infrun_async(0) ../../fixleaks/gdb/inferior.c:287: internal-error: inferior* find_inferior_pid(int): Assertion `pid != 0' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. Quit this debugging session? (y or n) FAIL: gdb.threads/watchthreads-reorder.exp: reorder1: continue to breakpoint: break-at-exit (GDB internal error) Resyncing due to internal error. n infrun: infrun_async(1) This is a bug, please report it. For instructions, see: . infrun: infrun_async(0) ../../fixleaks/gdb/inferior.c:287: internal-error: inferior* find_inferior_pid(int): Assertion `pid != 0' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. Create a core file of GDB? (y or n) y --- gdb/ChangeLog | 12 +++++++ gdb/gnu-nat.c | 10 ++---- gdb/infrun.c | 78 +++++++++-------------------------------- gdb/target/waitstatus.c | 3 +- 4 files changed, 31 insertions(+), 72 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index f3f30b1aa4c..ce9c573a8ef 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,15 @@ +2019-04-01 Philippe Waroquiers + + * infrun.c (stop_all_threads): If debug_infrun, always + trace the wait status after wait_one, using + target_waitstatus_to_string and target_pid_to_str. + (handle_inferior_event): Replace various trace of + wait status kind by a single trace. + * gdb/gnu-nat.c (gnu_nat_target::wait): Replace local + wait status kind image by target_waitstatus_to_string. + * target/waitstatus.c (target_waitstatus_to_string): Fix + obsolete comment. + 2019-04-01 Tom Tromey PR symtab/23331: diff --git a/gdb/gnu-nat.c b/gdb/gnu-nat.c index c1fafed156e..654a6527170 100644 --- a/gdb/gnu-nat.c +++ b/gdb/gnu-nat.c @@ -1647,15 +1647,9 @@ gnu_nat_target::wait (ptid_t ptid, struct target_waitstatus *status, inf_update_suspends (inf); } - inf_debug (inf, "returning ptid = %s, status = %s (%d)", + inf_debug (inf, "returning ptid = %s, %s", target_pid_to_str (ptid).c_str (), - status->kind == TARGET_WAITKIND_EXITED ? "EXITED" - : status->kind == TARGET_WAITKIND_STOPPED ? "STOPPED" - : status->kind == TARGET_WAITKIND_SIGNALLED ? "SIGNALLED" - : status->kind == TARGET_WAITKIND_LOADED ? "LOADED" - : status->kind == TARGET_WAITKIND_SPURIOUS ? "SPURIOUS" - : "?", - status->value.integer); + target_waitstatus_to_string (&status).c_str ()); return ptid; } diff --git a/gdb/infrun.c b/gdb/infrun.c index 0cfa2d6825d..28267411697 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -4358,24 +4358,21 @@ stop_all_threads (void) pass = -1; event_ptid = wait_one (&ws); - - if (ws.kind == TARGET_WAITKIND_NO_RESUMED) + if (debug_infrun) { - /* All resumed threads exited. */ + fprintf_unfiltered (gdb_stdlog, + "infrun: stop_all_threads %s %s\n", + target_waitstatus_to_string (&ws).c_str (), + target_pid_to_str (event_ptid).c_str ()); } - else if (ws.kind == TARGET_WAITKIND_THREAD_EXITED - || ws.kind == TARGET_WAITKIND_EXITED - || ws.kind == TARGET_WAITKIND_SIGNALLED) - { - if (debug_infrun) - { - ptid_t ptid = ptid_t (ws.value.integer); - fprintf_unfiltered (gdb_stdlog, - "infrun: %s exited while " - "stopping threads\n", - target_pid_to_str (ptid).c_str ()); - } + if (ws.kind == TARGET_WAITKIND_NO_RESUMED + || ws.kind == TARGET_WAITKIND_THREAD_EXITED + || ws.kind == TARGET_WAITKIND_EXITED + || ws.kind == TARGET_WAITKIND_SIGNALLED) + { + /* All resumed threads exited + or one thread/process exited/signalled. */ } else { @@ -4604,6 +4601,10 @@ handle_inferior_event (struct execution_control_state *ecs) enum stop_kind stop_soon; + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, "infrun: handle_inferior_event %s\n", + target_waitstatus_to_string (&ecs->ws).c_str ()); + if (ecs->ws.kind == TARGET_WAITKIND_IGNORE) { /* We had an event in the inferior, but we are not interested in @@ -4615,16 +4616,12 @@ handle_inferior_event (struct execution_control_state *ecs) not stopped, and we are ignoring the event. Another possible circumstance is any event which the lower level knows will be reported multiple times without an intervening resume. */ - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_IGNORE\n"); prepare_to_wait (ecs); return; } if (ecs->ws.kind == TARGET_WAITKIND_THREAD_EXITED) { - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_THREAD_EXITED\n"); prepare_to_wait (ecs); return; } @@ -4643,9 +4640,6 @@ handle_inferior_event (struct execution_control_state *ecs) { /* No unwaited-for children left. IOW, all resumed children have exited. */ - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_NO_RESUMED\n"); - stop_print_frame = 0; stop_waiting (ecs); return; @@ -4738,8 +4732,6 @@ handle_inferior_event (struct execution_control_state *ecs) switch (ecs->ws.kind) { case TARGET_WAITKIND_LOADED: - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_LOADED\n"); context_switch (ecs); /* Ignore gracefully during startup of the inferior, as it might be the shell which has just loaded some objects, otherwise @@ -4817,8 +4809,6 @@ handle_inferior_event (struct execution_control_state *ecs) _("unhandled stop_soon: %d"), (int) stop_soon); case TARGET_WAITKIND_SPURIOUS: - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_SPURIOUS\n"); if (handle_stop_requested (ecs)) return; context_switch (ecs); @@ -4827,8 +4817,6 @@ handle_inferior_event (struct execution_control_state *ecs) return; case TARGET_WAITKIND_THREAD_CREATED: - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_THREAD_CREATED\n"); if (handle_stop_requested (ecs)) return; context_switch (ecs); @@ -4838,16 +4826,6 @@ handle_inferior_event (struct execution_control_state *ecs) case TARGET_WAITKIND_EXITED: case TARGET_WAITKIND_SIGNALLED: - if (debug_infrun) - { - if (ecs->ws.kind == TARGET_WAITKIND_EXITED) - fprintf_unfiltered (gdb_stdlog, - "infrun: TARGET_WAITKIND_EXITED\n"); - else - fprintf_unfiltered (gdb_stdlog, - "infrun: TARGET_WAITKIND_SIGNALLED\n"); - } - inferior_ptid = ecs->ptid; set_current_inferior (find_inferior_ptid (ecs->ptid)); set_current_program_space (current_inferior ()->pspace); @@ -4912,14 +4890,6 @@ Cannot fill $_exitsignal with the correct signal number.\n")); the above cases end in a continue or goto. */ case TARGET_WAITKIND_FORKED: case TARGET_WAITKIND_VFORKED: - if (debug_infrun) - { - if (ecs->ws.kind == TARGET_WAITKIND_FORKED) - fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_FORKED\n"); - else - fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_VFORKED\n"); - } - /* Check whether the inferior is displaced stepping. */ { struct regcache *regcache = get_thread_regcache (ecs->event_thread); @@ -5080,10 +5050,6 @@ Cannot fill $_exitsignal with the correct signal number.\n")); /* Done with the shared memory region. Re-insert breakpoints in the parent, and keep going. */ - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, - "infrun: TARGET_WAITKIND_VFORK_DONE\n"); - context_switch (ecs); current_inferior ()->waiting_for_vfork_done = 0; @@ -5098,8 +5064,6 @@ Cannot fill $_exitsignal with the correct signal number.\n")); return; case TARGET_WAITKIND_EXECD: - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_EXECD\n"); /* Note we can't read registers yet (the stop_pc), because we don't yet know the inferior's post-exec architecture. @@ -5148,9 +5112,6 @@ Cannot fill $_exitsignal with the correct signal number.\n")); /* Be careful not to try to gather much state about a thread that's in a syscall. It's frequently a losing proposition. */ case TARGET_WAITKIND_SYSCALL_ENTRY: - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, - "infrun: TARGET_WAITKIND_SYSCALL_ENTRY\n"); /* Getting the current syscall number. */ if (handle_syscall_event (ecs) == 0) process_event_stop_test (ecs); @@ -5162,22 +5123,15 @@ Cannot fill $_exitsignal with the correct signal number.\n")); syscall. Stepping one instruction seems to get it back into user code.) */ case TARGET_WAITKIND_SYSCALL_RETURN: - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, - "infrun: TARGET_WAITKIND_SYSCALL_RETURN\n"); if (handle_syscall_event (ecs) == 0) process_event_stop_test (ecs); return; case TARGET_WAITKIND_STOPPED: - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_STOPPED\n"); handle_signal_stop (ecs); return; case TARGET_WAITKIND_NO_HISTORY: - if (debug_infrun) - fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_NO_HISTORY\n"); /* Reverse execution: target ran out of history info. */ /* Switch to the stopped thread. */ diff --git a/gdb/target/waitstatus.c b/gdb/target/waitstatus.c index 4ac98e50f4f..f86ce223739 100644 --- a/gdb/target/waitstatus.c +++ b/gdb/target/waitstatus.c @@ -20,8 +20,7 @@ #include "common/common-defs.h" #include "waitstatus.h" -/* Return a pretty printed form of target_waitstatus. - Space for the result is malloc'd, caller must free. */ +/* Return a pretty printed form of target_waitstatus. */ std::string target_waitstatus_to_string (const struct target_waitstatus *ws)