[asterisk-dev] Trunk: Transcoding causes lockups

[Steve Murphy]

On Mon, 2008-06-16 at 03:18 -0400, Brian Capouch wrote:
> Russell Bryant wrote:
> > 
> > Please try compiling with DEBUG_THREADS enabled.  Then, when it is  
> > locked up, grab the "core show locks" output.  That is usually enough  
> > information for us to fix the problem.  I know you said the CLI is  
> > dead, but try a remote console.
> > 
> > # asterisk -rx "core show locks" > locks.txt
> 
> (Written from the floor after falling off my chair . .  )
> 
> That fixed it!!
> 
> With total reproducibility, from the same source and with all other 
> options the same besides DEBUG_THREADS, the version with that build 
> option enabled works just fine.  The version built without DEBUG_THREADS 
> crashes every time.
> 

This is **so** "Murphy's Law"!
More than once,  I've gone into gdb to find a segv, 
only to find that it won't segv with the debugger operating.

I guess it could have been a time-sensitive lockup; using the thread
debug code changed the relative speed of the operations, and now
the two locks don't collide... or something!

Hmmm, I wonder if you could gdb attach to a running, deadlocked,
asterisk,
and get a 'thread apply all bt' and get any meaningful results....? Just
a thought...

murf


> I built each three times and carefully checked to make sure I was doing 
> the exact same thing in each case.
> 
> One thing I noticed is a slight difference on the CLI.
> 
> <Working>
> -- Executing Dial("SIP/spa3k-0078b258", "IAX2/carrier/12198666114")
>         > doing dnsmgr_lookup for 'sip.carrier.net'
>         > doing dnsmgr_lookup for 'sip.carrier.net'
>      -- Called carrier/12198666114
>         > doing dnsmgr_lookup for 'sip.carrier.net'
>      -- Call accepted by 1.2.3.4 (format gsm)
>      -- Format for call is gsm
>      -- IAX2/carrier-2895 is making progress passing it to 
> SIP/spa3k-0078b258
> </Working>
> 
> <Non-working>
> -- Executing Dial("SIP/spa3k-0078b258", "IAX2/carrier/12198666114")
>         > doing dnsmgr_lookup for 'sip.carrier.net'
>         > doing dnsmgr_lookup for 'sip.carrier.net'
>      -- Called carrier/12198666114
>         > doing dnsmgr_lookup for 'sip.carrier.net'
>      -- Call accepted by 1.2.3.4 (format gsm)
>      -- Format for call is gsm
> </Non-working>
> *** All sounds stop at this point and system is hung *****
> 
> This is r122766.
> 
> Thanks.
> 
> b.
> 
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-- 
Steve Murphy
Software Developer
Digium
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