glibc pthread_cond_timedwait deadlock

Issue

• We are investigating and issue which causes sporadic but recurring hangs. It looks like a pthread_cond_timedwait deadlock in glibc. There are various reports on the Internet that this function has been or is buggy. The small program to reproduce the problem produces the same stack traces that we observe in our hanging process. This is mentioned on the glibc bug tracker and Launchpad:

• glibc Bugzilla 25847 - pthread_cond_signal failed to wake up pthread_cond_wait due to a bug in undoing stealing

• Ubuntu glibc bug 1899800 - Runtime deadlock: pthread_cond_signal failed to wake up pthread_cond_wait due to a bug in undoing stealing