Date: Wed, 12 Sep 2001 16:43:52 -0400 (EDT) From: Jeff Fellin <jkf@research.bell-labs.com> To: freebsd-questions@freebsd.ORG Subject: Linux threads loses signal Message-ID: <200109122043.QAA23910@zydeco.research.bell-labs.com>
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We have an application using the linuxthreads package, version 2.1.3_2,
installed on FreeBSD 4.3. The application occassionally gets blocked
waiting in pthread_cond_timedwait_relative_old(), at least from the
stack trace. There are many threads, 13, in the application each calling
pthread_cond_timedwait. We have been unable to recreate the problem
in a smaller program, since we don't understand what is happening in
the linuxthreads library with cond_timedwait.
To help determine where the problem was we modified the file, condvar.c,
around line 220, by adding two print statements shown below:
if (!was_signalled) {
if (atomic_increment(&self->p_resume_count) != -1) {
printf ("***********Waiting for restart signal from %x, resume_count
%d\n",
(int)self, (int)(self->p_resume_count.p_count));
__pthread_wait_for_restart_signal(self);
printf ("***********Received restart signal from %x\n", (int)self);
atomic_decrement(&self->p_resume_count); /* should be zero now! */
When the thread blocks the last message printed is:
***********Waiting for restart signal from bedffe60, resume_count 1
But I never see that the restart signal was received.
Does any one have ideas on what the problem might be and/or a fix?
Is there additional information that would be helpful to print?
Jeff Fellin
Bell Labs
600 Mountain Ave.
Murray Hill, NJ 07974
fellin@lucent.com
908 582-7673
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