Firefox/Thunderbird and SSL not working with libthread_xu

Matthew Dillon dillon at
Sat Apr 12 10:47:06 PDT 2008

:> :strange. Below is a commented extract from the 'kdump -T' output.
:> :// thread #4 calls umtx_sleep on 0x2a92f664
:> :// thread #4 never returns from this syscall, according to the kdump output
:> :75875:4    firefox-bin 1207996217.713757 CALL  umtx_sleep(0x2a92f664,0,0)
:> :// thread #1 attempts to wake up thread #4
:> :75875:1    firefox-bin 1207996244.646643 CALL  
:> :umtx_wakeup(0x2a92f664,0x7fffffff)
:> :// I terminate the process
:> :75875:5    firefox-bin 1207996413.782573 PSIG  SIGQUIT SIG_DFL
:> :
:> :The expected behaviour is for thread #4 to wake up when thread #1 calls 
:> :umtx_wakeup.
:> :
:> :I'd appreciate any feedback on the issue.
:> :If you need information about my environment, I'd be happy to provide it.
:>     Could you paste all the ofktrace output between those two points?  It
:>     definitely should have woken up thread 4.
:> 					-Matt
:> 					Matthew Dillon 
:> 					<dillon at>
:There are about 2 million lines of kdump output between these two 
:points, which include the output of some debugging printfs and likely 
:information read from/written to my personal profile. The only mentions 
:of 0x2a92f664 in the kdump output are the lines pasted above. And, as I 
:said, no return from umtx_sleep for thread 4 is noticed by ktrace. 
:Before I terminated the process I ran 'ps -axHl' which resulted in the 
:following line, among others:
: 1001 75875     4 74331  79 200   0 54880 43764 umtxsl IL+   p6    
:0:00.00 /usr/pkg/lib/firefox/firefox-bin
:Notice the 'I' in 'IL+'.
:The issue is very easy to reproduce - just run 'ktrace -i firefox' and 
:try to open an SSL site. If opening the site fails, then close the 
:window, wait for some time, then terminate the process. If opening the 
:SSL site succeeds, just try again.
:I've reproduced the issue with thunderbird too, where the thread than 
:never woke up happened to be thread #5. I'm running DragonFly 1.12.1 
:with UP kernel.
:I ask anybody who doesn't trust my results to try and reproduce the issue.

    I trust them, I just want to see what else is going on... for example,
    if the memory in question is remapped inbetween the sleep and the

    2 million lines isn't too bad, but not something to post to a mailing
    list.  Could you throw them up on a machine that I can download from?
    I can give you a leaf account if you need a machine to upload the
    output to.

					Matthew Dillon 
					<dillon at>

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