Comment 3 for bug 1572287

Observed in build 32 also.

(gdb) bt
#0 0x00007f48b86ab010 in ?? ()
#1 0x0000000000b5396b in KSyncObject::NotifyEvent(KSyncEntry*, KSyncEntry::KSyncEvent) ()
#2 0x0000000000b53c3d in KSyncObject::SafeNotifyEvent(KSyncEntry*, KSyncEntry::KSyncEvent) ()
#3 0x0000000000b55430 in KSyncObjectManager::Process(KSyncObjectEvent*) ()
#4 0x0000000000b5aeff in QueueTaskRunner<KSyncObjectEvent*, WorkQueue<KSyncObjectEvent*> >::Run() ()
#5 0x0000000000f47afc in TaskImpl::execute() ()
#6 0x00007f48ce45bb3a in ?? () from /usr/lib/libtbb.so.2
#7 0x00007f48ce457816 in ?? () from /usr/lib/libtbb.so.2
#8 0x00007f48ce456f4b in ?? () from /usr/lib/libtbb.so.2
#9 0x00007f48ce4530ff in ?? () from /usr/lib/libtbb.so.2
#10 0x00007f48ce4532f9 in ?? () from /usr/lib/libtbb.so.2
#11 0x00007f48ce677182 in start_thread (arg=0x7f48c6b12700) at pthread_create.c:312
#12 0x00007f48cd95047d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111