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[RFAv2] Fix internal error and improve 'set debug infrun 1'/target wait kind trace
- From: Philippe Waroquiers <philippe dot waroquiers at skynet dot be>
- To: gdb-patches at sourceware dot org
- Cc: Philippe Waroquiers <philippe dot waroquiers at skynet dot be>
- Date: Sat, 30 Mar 2019 10:58:31 +0100
- Subject: [RFAv2] 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
2019-03-30 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* 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 <internal_error_problem>, file=<optimized out>, line=287,
fmt=<optimized out>, ap=<optimized out>) at ../../fixleaks/gdb/utils.c:411
#4 0x0000555c24c63eab in internal_verror (file=<optimized out>, line=<optimized out>, fmt=<optimized out>,
ap=<optimized out>) at ../../fixleaks/gdb/utils.c:436
#5 0x0000555c249e8c22 in internal_error (file=file@entry=0x555c24e0f2ad "../../fixleaks/gdb/inferior.c",
line=line@entry=287, fmt=<optimized out>) at ../../fixleaks/gdb/common/errors.c:55
#6 0x0000555c247d3f5c in find_inferior_pid (pid=<optimized out>) at ../../fixleaks/gdb/inferior.c:287
#7 0x0000555c24ad2248 in find_inferior_pid (pid=<optimized out>) 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 <the_thread_db_target>, 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=<optimized out>) 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:
<http://www.gnu.org/software/gdb/bugs/>.
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/gnu-nat.c | 10 ++----
gdb/infrun.c | 78 +++++++++--------------------------------
gdb/target/waitstatus.c | 3 +-
3 files changed, 19 insertions(+), 72 deletions(-)
diff --git a/gdb/gnu-nat.c b/gdb/gnu-nat.c
index c1fafed156..654a652717 100644
--- a/gdb/gnu-nat.c
+++ b/gdb/gnu-nat.c
@@ -1647,15 +1647,9 @@ rewait:
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 0cfa2d6825..2826741169 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 4ac98e50f4..f86ce22373 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)
--
2.20.1