Messages in this thread | | | Date | Sat, 17 May 2008 15:45:57 +0200 | From | Takashi Iwai <> | Subject | Re: [Bugme-new] [Bug 10701] New: snd_pcsp lockdep warning |
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At Fri, 16 May 2008 21:32:49 +0200 (CEST), Thomas Gleixner wrote: > > On Fri, 16 May 2008, Andrew Morton wrote: > > > So the author was well aware of locking problem and the whole code is > > > just a stupid hack around the problem without solving it. This code is > > > not at all suited for HRTIMER_CB_IRQSAFE. > > > > You sound impressed! So what's the fix? HRTIMER_CB_SOFTIRQ? > > Yeah, impressed by creativity. HRTIMER_CB_SOFTIRQ should be the right > thing.
Well, it'd be basically a similar way like snd-pcsp currently does ("a stupid hack" :) But, it's good to have a fix, anyway, since this sounds like a generic problem with a callback in a spinlock. If the callback requires another own lock, this can easily lead to a AB/BA deadlock. Actually, ALSA PCM core had sometimes similar problems, too.
thanks,
Takashi
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