firefox gets stuck every once in a while

[Mikhail T.]

Hello!

Every once in a while FireFox gets "stuck" on my machine consuming all
available CPU.

Attaching a debugger to the process shows a stack like this:

#0  0x0000000803119a38 in read () from /lib/libc.so.5
#1  0x0000000802f9edfb in read () from /usr/lib/libpthread.so.1
#2  0x00000008008858f6 in PL_EventLoop () from /opt/lib/firefox/libxpcom.so
#3  0x0000000800885560 in PL_ProcessPendingEvents () from /opt/lib/firefox/libxpcom.so
#4  0x0000000800886f77 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#5  0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#6  0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#7  0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#8  0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#9  0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#10 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#11 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#12 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#13 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#14 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#15 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#16 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#17 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#18 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#19 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#20 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#21 0x0000000800887012 in nsEventQueueImpl::NotifyObservers () from /opt/lib/firefox/libxpcom.so
#22 0x0000000808748429 in nsXMLHttpRequest::RequestCompleted () from /opt/lib/firefox/components/libxmlextras.so
#23 0x00000008008a1f27 in XPTC_InvokeByIndex () from /opt/lib/firefox/libxpcom.so
#24 0x0000000803994a9d in XPCWrappedNative::CallMethod () from /opt/lib/firefox/components/libxpconnect.so
#25 0x000000080399c6f9 in XPC_WN_CallMethod () from /opt/lib/firefox/components/libxpconnect.so
#26 0x00000008006808fc in js_Invoke () from /opt/lib/firefox/libmozjs.so
[...]

According to ktrace, all it is doing is:

 92514 firefox-bin CALL  read(0x3d,0x7fffffffb4a7,0x1) 92514 firefox-bin RET   read -1 errno 35 Resource temporarily unavailable
 92514 firefox-bin CALL  read(0x29,0x7fffffffb487,0x1) 92514 firefox-bin RET   read -1 errno 35 Resource temporarily unavailable
 92514 firefox-bin CALL  read(0x26,0x7fffffffb467,0x1) 92514 firefox-bin RET   read -1 errno 35 Resource temporarily unavailable
[... ad infinum ...]

Does this arouse any ideas in anyone? I'm using a recent 5.4 on
FreeBSD/amd64.

Thanks!

	-mi