Messages in this thread | | | Subject | Re: [PATCH/RFC] mutex: Fix optimistic spinning vs. BKL | From | Benjamin Herrenschmidt <> | Date | Wed, 28 Apr 2010 14:39:34 +1000 |
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On Wed, 2010-04-28 at 14:38 +1000, Benjamin Herrenschmidt wrote: > Currently, we can hit a nasty case with optimistic spinning on mutexes: > > CPU A tries to take a mutex, while holding the BKL > > CPU B tried to take the BLK while holding the mutex > > This looks like a AB-BA scenario but in practice, is allowed and happens > due to the auto-release-on-schedule nature of the BKL.
.../...
BTW. The patch is only compile-tested so far :-) It's going to be hammered with the test case that triggered the original bug hopefully tonight.
Cheers, Ben.
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