From 9665ffdd591e9b374b4e5f6aeffe15541346140d Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Mon, 29 Dec 2014 19:41:04 +0000 Subject: [PATCH] gdb.threads/{siginfo-thread.c,watchthreads-reorder.c,ia64-sigill.c} races with GDB These three test all spawn a few threads and then send a SIGSTOP to their parent GDB in order to pause it while the new threads set things up for the test. With a GDB patch that changes the inferior thread's scheduling a bit, I sometimes see: FAIL: gdb.threads/siginfo-threads.exp: catch signal 0 (timeout) ... FAIL: gdb.threads/watchthreads-reorder.exp: reorder1: continue a (timeout) ... FAIL: gdb.threads/ia64-sigill.exp: continue (timeout) ... The issue is that the test program stops GDB before it had a chance of processing the new thread's clone event: (gdb) PASS: gdb.threads/siginfo-threads.exp: get pid continue Continuing. Stopping GDB PID 21541. Waiting till the threads initialize their TIDs. FAIL: gdb.threads/siginfo-threads.exp: catch signal 0 (timeout) On Linux (at least), new threads start stopped, and the debugger must resume them. The fix is to make the test program wait for the new threads to be running before stopping GDB. gdb/testsuite/ 2015-01-09 Pedro Alves * gdb.threads/ia64-sigill.c (threads_started_barrier): New global. (thread_func): Wait on barrier. (main): Wait for all threads to start before stopping GDB. * gdb.threads/siginfo-threads.c (threads_started_barrier): New global. (thread1_func, thread2_func): Wait on barrier. (main): Wait for all threads to start before stopping GDB. * gdb.threads/watchthreads-reorder.c (threads_started_barrier): New global. (thread1_func, thread2_func): Wait on barrier. (main): Wait for all threads to start before stopping GDB. --- gdb/testsuite/ChangeLog | 14 ++++++++++++++ gdb/testsuite/gdb.threads/ia64-sigill.c | 11 +++++++++++ gdb/testsuite/gdb.threads/siginfo-threads.c | 13 +++++++++++++ gdb/testsuite/gdb.threads/watchthreads-reorder.c | 13 +++++++++++++ 4 files changed, 51 insertions(+) diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 77758f18ad..cd38459b69 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,17 @@ +2015-01-09 Pedro Alves + + * gdb.threads/ia64-sigill.c (threads_started_barrier): New global. + (thread_func): Wait on barrier. + (main): Wait for all threads to start before stopping GDB. + * gdb.threads/siginfo-threads.c (threads_started_barrier): New + global. + (thread1_func, thread2_func): Wait on barrier. + (main): Wait for all threads to start before stopping GDB. + * gdb.threads/watchthreads-reorder.c (threads_started_barrier): + New global. + (thread1_func, thread2_func): Wait on barrier. + (main): Wait for all threads to start before stopping GDB. + 2015-01-09 Pedro Alves * gdb.threads/attach-many-short-lived-threads.c: New file. diff --git a/gdb/testsuite/gdb.threads/ia64-sigill.c b/gdb/testsuite/gdb.threads/ia64-sigill.c index 6af01385e1..11782fad34 100644 --- a/gdb/testsuite/gdb.threads/ia64-sigill.c +++ b/gdb/testsuite/gdb.threads/ia64-sigill.c @@ -44,6 +44,8 @@ static pthread_mutex_t thread2_tid_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_ static pthread_mutex_t terminate_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; +static pthread_barrier_t threads_started_barrier; + /* Do not use alarm as it would create a ptrace event which would hang up us if we are being traced by GDB which we stopped ourselves. */ @@ -78,6 +80,8 @@ thread_func (void *threadno_voidp) int threadno = (intptr_t) threadno_voidp; int i; + pthread_barrier_wait (&threads_started_barrier); + switch (threadno) { case 1: @@ -272,6 +276,8 @@ main (int argc, char **argv) timed_mutex_lock (&terminate_mutex); + pthread_barrier_init (&threads_started_barrier, NULL, 3); + i = pthread_create (&thread1, NULL, thread_func, (void *) (intptr_t) 1); assert (i == 0); @@ -298,6 +304,11 @@ main (int argc, char **argv) atexit (cleanup); + /* Wait until all threads are seen running. On Linux (at least), + new threads start stopped, and the debugger must resume them. + Need to wait for that before stopping GDB. */ + pthread_barrier_wait (&threads_started_barrier); + printf ("Stopping GDB PID %lu.\n", (unsigned long) tracer); if (tracer) diff --git a/gdb/testsuite/gdb.threads/siginfo-threads.c b/gdb/testsuite/gdb.threads/siginfo-threads.c index 95c3927aef..a8e54463bd 100644 --- a/gdb/testsuite/gdb.threads/siginfo-threads.c +++ b/gdb/testsuite/gdb.threads/siginfo-threads.c @@ -54,6 +54,8 @@ static int thread2_sigusr2_hit; static pthread_mutex_t terminate_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; +static pthread_barrier_t threads_started_barrier; + /* Do not use alarm as it would create a ptrace event which would hang us up if we are being traced by GDB, which we stopped ourselves. */ @@ -128,6 +130,8 @@ thread1_func (void *unused) { int i; + pthread_barrier_wait (&threads_started_barrier); + timed_mutex_lock (&thread1_tid_mutex); /* THREAD1_TID_MUTEX must be already locked to avoid a race. */ @@ -163,6 +167,8 @@ thread2_func (void *unused) { int i; + pthread_barrier_wait (&threads_started_barrier); + timed_mutex_lock (&thread2_tid_mutex); /* THREAD2_TID_MUTEX must be already locked to avoid a race. */ @@ -354,6 +360,8 @@ main (int argc, char **argv) assert_perror (errno); assert (i == 0); + pthread_barrier_init (&threads_started_barrier, NULL, 3); + i = pthread_create (&thread1, NULL, thread1_func, NULL); assert (i == 0); @@ -380,6 +388,11 @@ main (int argc, char **argv) atexit (cleanup); + /* Wait until all threads are seen running. On Linux (at least), + new threads start stopped, and the debugger must resume them. + Need to wait for that before stopping GDB. */ + pthread_barrier_wait (&threads_started_barrier); + printf ("Stopping GDB PID %lu.\n", (unsigned long) tracer); if (tracer) diff --git a/gdb/testsuite/gdb.threads/watchthreads-reorder.c b/gdb/testsuite/gdb.threads/watchthreads-reorder.c index 353b4a16ea..b28a0dea82 100644 --- a/gdb/testsuite/gdb.threads/watchthreads-reorder.c +++ b/gdb/testsuite/gdb.threads/watchthreads-reorder.c @@ -44,6 +44,8 @@ static pthread_mutex_t thread2_tid_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_ static pthread_mutex_t terminate_mutex = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP; +static pthread_barrier_t threads_started_barrier; + /* These variables must have lower in-memory addresses than thread1_rwatch and thread2_rwatch so that they take their watchpoint slots. */ @@ -87,6 +89,8 @@ thread1_func (void *unused) int i; volatile int rwatch_store; + pthread_barrier_wait (&threads_started_barrier); + timed_mutex_lock (&thread1_tid_mutex); /* THREAD1_TID_MUTEX must be already locked to avoid race. */ @@ -113,6 +117,8 @@ thread2_func (void *unused) int i; volatile int rwatch_store; + pthread_barrier_wait (&threads_started_barrier); + timed_mutex_lock (&thread2_tid_mutex); /* THREAD2_TID_MUTEX must be already locked to avoid race. */ @@ -279,6 +285,8 @@ main (int argc, char **argv) timed_mutex_lock (&terminate_mutex); + pthread_barrier_init (&threads_started_barrier, NULL, 3); + i = pthread_create (&thread1, NULL, thread1_func, NULL); assert (i == 0); @@ -305,6 +313,11 @@ main (int argc, char **argv) atexit (cleanup); + /* Wait until all threads are seen running. On Linux (at least), + new threads start stopped, and the debugger must resume them. + Need to wait for that before stopping GDB. */ + pthread_barrier_wait (&threads_started_barrier); + printf ("Stopping GDB PID %lu.\n", (unsigned long) tracer); if (tracer) -- 2.34.1