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Date:      Sat, 11 Oct 2003 19:37:53 +1000
From:      CJ East <ghd832332157@geckomail.org>
To:        freebsd-questions@freebsd.org
Subject:   Malloc debugging for snd_pcm
Message-ID:  <1065865072.2409.7.camel@buttercup.trl.telstra.com.au>

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Hi all :P 

My apologies if this is a fixed problem/etc I'm new to FreeBSD so here
goes... 

Additionally, my apologies if my this is the inappropriate list for
discussion of this problem- if you would be so kind as to let me know
where it would be more appropriate, please do so... 

I'm running a world build from cvs tagged RELENG_5_1 a little over a
week ago.  I'm as yet to figure out what that branch is called... 

Disclaimers away, here's the meat... 
====================================

PR Kern/40711 looks very similar to the problem I'm having, it looks to
have the same symptoms as my own, however my looking has lead me to
snd_pcm.ko module as the root cause.  (The driver I'm using is in fact
snd_ich) 

Specifically, I can reproduce the problem (making hw.snd.pcm0.vchans=8) 
and have taken it as far as sndbuf_remalloc (in
/usr/src/sys/dev/sound/pcm/buffer.c), in which one of two malloc calls
fail, unwinding all the way to the top where xmms prints it's lovely
message. 

The actual call to malloc looks sane enough to my eyes (131072 bytes, it
does this successfully beforehand so I'm guessing no probs there).
I'm suspecting that there's a leak somewhere and we've hit a hard limit.
(Of course, I'm just stabbing in the dark, so let me know if y'all have
another idea) 
 
If somebody could let me know where to run with this it would be quite
helpful (I'm assuming there's some way of checking the amount allocated
to M_DEVBUF, but I've no idea how! :( )  -- I can reproduce the problem
(reasonably sporadically, about once an hour or so with xmms playing) 

I looked at the underlying malloc function but I'm a little retiscent to
start putting printf's in there... ;)   What's the best course of action
somebody?  



-cje- 



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