Date: Sun, 9 May 2004 10:53:56 +0200 From: Bartek Marcinkiewicz <junior@p233.if.pwr.wroc.pl> To: freebsd-hackers@freebsd.org Subject: non-recursive mutex, sbc, pcm, kernel panic Message-ID: <20040509085356.GA15318@p233.if.pwr.wroc.pl>
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Hello,
I've just experienced kernel panic while trying
to play mp3 file. (My sound card: Creative Sound
Blaster 16, ISA, worked fine on older 5.x system).
While reading code:
sys/dev/sound/pcm/sound.c::snd_mtxcreate() creates
non-recursive mutex.
But in sys/dev/sound/isa/sb16.c::sb_setup() we have:
sb_setup()
{
sb_lock(sb);
/* ... */
sb_reset_dsp(sb);
/* ... */
}
sb_reset_dsp() function locks this mutex again, causing
panic with message:
_mtx_lock_sleep: recursed on non-recursive mutex sbc0 @...
Is this known issue? Why this mutex should be non-recursive?
Attached patch makes it work again.
best regards, bm.
FreeBSD 5.2-CURRENT FreeBSD Sat Mar 27 18:25:15 CET 2004
sbc0: <Creative ViBRA16C> at port 0x388-0x38b,0x330-0x331,0x220-0x22f
irq 5 drq 5,1 on isa0
sbc0: [GIANT-LOCKED]
pcm0: <SB16 DSP 4.13> on sbc0
--- sound.c Sun May 9 10:44:20 2004
+++ sound.c Sun May 9 10:48:31 2004
@@ -75,7 +75,7 @@
m = malloc(sizeof(*m), M_DEVBUF, M_WAITOK | M_ZERO);
if (m == NULL)
return NULL;
- mtx_init(m, desc, type, MTX_DEF);
+ mtx_init(m, desc, type, MTX_DEF | MTX_RECURSE);
return m;
#else
return (void *)0xcafebabe;
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