I found a coredump in my ~ from a few days ago.

Core was generated by `/usr/lib64/firefox-1.5/firefox-bin -UILocale en-US'.
Program terminated with signal 11, Segmentation fault.

...

(gdb) bt
#0  0x0000003c3dd0cab9 in raise () from /lib64/libpthread.so.0
#1  0x000000000041350b in nsProfileLock::FatalSignalHandler (signo=11) at
nsProfileLock.cpp:206
#2  <signal handler called>
#3  0x00002b48b6211643 in PL_DHashTableOperate (table=0x59bd388,
key=0x2aaaac208890, op=PL_DHASH_ADD) at pldhash.c:492
#4  0x00002b48b621cb77 in nsBaseHashtable<nsCharPtrHashKey,
nsCOMPtr<nsISupports>, nsISupports*>::Put (this=Variable "this" is not available.
)
    at ../../dist/include/xpcom/nsBaseHashtable.h:145
#5  0x00002b48b621c7bf in nsProperties::Set (this=Variable "this" is not available.
) at nsProperties.cpp:77
#6  0x00002aaaac1fe631 in imgRequest::OnDataAvailable (this=0x59bd0f0,
aRequest=0x59bc6f8, ctxt=Variable "ctxt" is not available.
)
    at imgRequest.cpp:825
#7  0x00002b48b9f12b62 in nsStreamListenerTee::OnDataAvailable (this=0x36f2b20,
request=0x59bc6f8, context=0x0,
    input=0x59bdd00, offset=0, count=2590) at nsStreamListenerTee.cpp:97
#8  0x00002b48b9f60e33 in nsHttpChannel::OnDataAvailable (this=0x59bc6b0,
request=Variable "request" is not available.
) at nsHttpChannel.cpp:4182
#9  0x00002b48b9efc523 in nsInputStreamPump::OnStateTransfer (this=0x59bdec0) at
nsInputStreamPump.cpp:437
#10 0x00002b48b9efc607 in nsInputStreamPump::OnInputStreamReady (this=0x59bdec0,
stream=Variable "stream" is not available.
) at nsInputStreamPump.cpp:340
#11 0x00002b48b6237f11 in nsInputStreamReadyEvent::EventHandler
(plevent=Variable "plevent" is not available.
) at nsStreamUtils.cpp:119
#12 0x00002b48b624899f in PL_HandleEvent (self=0x59bdfc8) at plevent.c:688
#13 0x00002b48b6248bb1 in PL_ProcessPendingEvents (self=0x5d8790) at plevent.c:623
#14 0x00002b48b6249f7b in nsEventQueueImpl::ProcessPendingEvents (this=0x59e4c0)
at nsEventQueue.cpp:417
#15 0x00002aaaaaf1b942 in event_processor_callback (source=Variable "source" is
not available.
) at nsAppShell.cpp:67
#16 0x0000003cdc224e91 in g_main_context_dispatch () from
/usr/lib64/libglib-2.0.so.0
#17 0x0000003cdc227cad in g_main_context_check () from /usr/lib64/libglib-2.0.so.0
#18 0x0000003cdc227ffe in g_main_loop_run () from /usr/lib64/libglib-2.0.so.0
#19 0x000000367ce0bf55 in gtk_main () from /usr/lib64/libgtk-x11-2.0.so.0
#20 0x00002aaaaaf1bc72 in nsAppShell::Run (this=0x6c1c50) at nsAppShell.cpp:139
#21 0x00002aaaab391464 in nsAppStartup::Run (this=0x6c1bd0) at nsAppStartup.cpp:150
#22 0x000000000040b20b in XRE_main (argc=Variable "argc" is not available.
) at nsAppRunner.cpp:2313
#23 0x0000003c3b91cde4 in __libc_start_main () from /lib64/libc.so.6
#24 0x0000000000406b29 in _start ()
#25 0x00007fffff9f1088 in ?? ()
#26 0x0000000000000000 in ?? ()