Re: LOR pcm0:play:0 / kernel environment

On Mon, 8 Aug 2005 02:20:11 -0700 (PDT)
Don Lewis <truckman_at_FreeBSD.org> wrote:
> On  5 Aug, Alexander Leidinger wrote:
> > Antoine Brodin <antoine.brodin_at_laposte.net> wrote:
> > 
> > CCing multimedia_at_, since there are the people which may be able to
> > solve ths issue.
> > 
> >> I have a LOR that doesn't seem to be on the LOR page:
> >>
> >> lock order reversal
> >> 1st 0xc30b3b00 pcm0:play:0 (pcm play channel) _at_ 
> >>
> >/usr/src/sys/modules/sound/sound/../../../dev/sound/pcm/channel.c:
> >1134 > 2nd 0xc06a7900 kernel environment (kernel environment) _at_ 
> >> /usr/src/sys/kern/subr_hints.c:117
> >> KDB: stack backtrace:
> >> kdb_backtrace(c065a9a4,c06a7900,c0653c0b,c0653c0b,c0658e0a) at 
> >> kdb_backtrace+0x2e
> >> witness_checkorder(c06a7900,1,c0658e0a,75,e62c9a04) at 
> >> witness_checkorder+0x6c3
> >> _sx_slock(c06a7900,c0658e0a,75,c0656022,18b) at _sx_slock+0x7e
> >> res_find(e62c9b44,0,c2ff42ec,e62c9b58,c0e74b0a) at res_find+0x1bd
> >> resource_find(e62c9b44,0,c2ff42ec,e62c9b58,c0e74b0a) at
> >resource_find+0x67 >
> >resource_int_value(c2ff42ec,0,c0e74b0a,e62c9b70,c30c0100) at  >
> >resource_int_value+0x6c > vchan_create(c30c0100,0,c0e746b1,100,4)
> >at vchan_create+0x32d >
> >sysctl_hw_snd_maxautovchans(c0e778e0,0,4,e62c9bfc,e62c9bfc) at  >
> >sysctl_hw_snd_maxautovchans+0x207 >
> >sysctl_root(0,e62c9c6c,3,e62c9bfc,c3080320) at sysctl_root+0x14e >
> >userland_sysctl(c3080320,e62c9c6c,3,0,0) at userland_sysctl+0x122 >
> >__sysctl(c3080320,e62c9d04,18,422,6) at __sysctl+0xb7 >
> >syscall(3b,3b,3b,0,bfbfee10) at syscall+0x2a2 > Xint0x80_syscall()
> >at Xint0x80_syscall+0x1f > --- syscall (202, FreeBSD ELF32,
> >__sysctl), eip = 0x2812f17b, esp =  > 0xbfbfe55c, ebp = 0xbfbfe588
> >---
> 
> The last time I looked at the auto vchan code, I came to the
> conclusion that it needed to be re-written.  It looked to me like
> there were some nasty-looking locking problems and that the vchans
> and unit numbers could get out of sync.  I'd recommend manually
> setting the number of vchans with the hw.snd.pcm*.vchans sysctl
> knob.
> 
Yeah, agreed, in fact, my latest patch already rewrote large part of
it, increase robustness here and there. It is just a matter of time
before I should post the announcement about latest major overhaul.

If anybody interested, please get the diffs from
  http://staff.mybsd.org.my/skywizard/FreeBSD/sound/
(yes, fix for this LOR included)


--

Ariff Abdullah
MyBSD

http://www.MyBSD.org.my (IPv6/IPv4)
http://staff.MyBSD.org.my (IPv6/IPv4)
http://tomoyo.MyBSD.org.my (IPv6/IPv4)