Comment 2 for bug 790929

bt:

#0 0x0000003fccc0bd02 in pthread_kill () from /lib64/libpthread.so.0
#1 0x00000000008c8393 in my_write_core (sig=11) at /mnt/x25m/gval/r3483/mysys/stacktrace.c:423
#2 0x00000000005395a7 in handle_segfault (sig=11) at /mnt/x25m/gval/r3483/sql/mysqld.cc:2546
#3 <signal handler called>
#4 0x0000000000b7e95f in min_heap_erase (s=0x15e74a8, e=0x2aaab0001070) at /mnt/x25m/gval/r3483/extra/libevent/min_heap.h:88
#5 0x0000000000b7e8ae in event_queue_remove (base=0x15e72a0, ev=0x2aaab0001070, queue=1) at /mnt/x25m/gval/r3483/extra/libevent/event.c:925
#6 0x0000000000b7e23f in event_del (ev=0x2aaab0001070) at /mnt/x25m/gval/r3483/extra/libevent/event.c:780
#7 0x00000000006aff5a in libevent_thread_proc (arg=0x0) at /mnt/x25m/gval/r3483/sql/scheduler.cc:606
#8 0x0000003fccc0673d in start_thread () from /lib64/libpthread.so.0
#9 0x0000003fcc4d3f6d in clone () from /lib64/libc.so.6