Firefox (MozillaFirefox-38.0.6-1.3.x86_64) is crashing when following links
like bugzilla's login or a search result on google.

A quick gdb attach w/o debuginfo shows a segfault in pthread_mutex_lock.

(gdb) continue
Continuing.
[New Thread 0x7f96162fc700 (LWP 2566)]
[New Thread 0x7f962b4ff700 (LWP 2563)]
[New Thread 0x7f962e1fe700 (LWP 2562)]
[New Thread 0x7f9635149700 (LWP 2561)]
[New Thread 0x7f962d9fd700 (LWP 2560)]
[New Thread 0x7f9634948700 (LWP 2559)]
[New Thread 0x7f9621ffc700 (LWP 2557)]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7f961e7ff700 (LWP 2372)]
0x00007f964eef7894 in pthread_mutex_lock () from /lib64/libpthread.so.0
(gdb)