lock order reversal

[Georg Funk]

hm, the patch doesn't seem to work:

--------------------------------------------------
#patch < pcm.diff
Hmm...  Looks like a normal diff to me...
The text leading up to this was:
--------------------------
|cvs diff: Diffing sys/dev/sound/pcm
|Index: sys/dev/sound/pcm/dsp.c
|===================================================================
|RCS file: 
/old/pub/FreeBSD/development/FreeBSD-CVS/src/sys/dev/sound/pcm/dsp.c,v
|retrieving revision 1.62
|diff -r1.62 dsp.c
--------------------------
Patching file dsp.c using Plan A...
Hunk #1 failed at 265.
Hunk #2 failed at 270.
Hunk #3 failed at 287.
Hunk #4 succeeded at 304.
3 out of 4 hunks failed--saving rejects to dsp.c.rej
done

On Wednesday 30 April 2003 16:33, you wrote:
> On Wednesday 30 April 2003 14:55, Georg Funk wrote:
> > Hi!
> > I'm running the FreeBSD 5.0-RELEASE. When I boot up, this appears:
> >
> > 1st 0xc12a7230 process lock (process lock) @
> > ../../../kern/kern_descrip.c:2112 lock order reversal
> > I haven't noticed any disfunctions, but what does this mean?
> >
> > I get a similar error when I use my soundcard:
> >
> > lock order reversal
> >  1st 0xc120a680 pcm0 (sound softc) @ ../../../dev/sound/isa/mss.c:177
> >  2nd 0xc120a740 pcm0:play:0 (pcm channel) @
> > ../../../dev/sound/pcm/channel.c:441
> >
> > I have to restart the KDE artsd before the soundcard works correct.
> > Please give me advice how to solve this.
> >
> > Thanks in advance, Georg Funk
>
> I have also seen that problem, and this patch seems to work here..
> It is probably not very optimized, but the lock order reversal didn't show
> up again...
>
> cvs diff: Diffing sys/dev/sound/pcm
> Index: sys/dev/sound/pcm/dsp.c
> ===================================================================
> RCS file:
> /old/pub/FreeBSD/development/FreeBSD-CVS/src/sys/dev/sound/pcm/dsp.c,v
> retrieving revision 1.62
> diff -r1.62 dsp.c
> 265,266c265
> <       pcm_unlock(d);
> <       /* finished with snddev, new channels still locked */
> ---
>
> >       /* keep the snddev lock to avoid a lock order reversal, new
> > channels still locked */
>
> 271d269
> <                       pcm_lock(d);
> 289d286
> <                       pcm_lock(d);
> 306a304
>
> >       pcm_unlock(d);
>
> Regards,
> Jan-Espen Pettersen
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