Messages in this thread | | | Date | Thu, 01 Apr 2010 14:09:30 +0300 | From | Avi Kivity <> | Subject | Re: [COUNTERPATCH] mm: avoid overflowing preempt_count() in mmu_take_all_locks() |
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On 04/01/2010 01:31 PM, Peter Zijlstra wrote: > I'm sure you dropped Ingo and Thomas by accident. > > On Thu, 2010-04-01 at 12:40 +0300, Avi Kivity wrote: > >> mmu_take_all_locks() takes a spinlock for each vma, which means we increase >> the preempt count by the number of vmas in an address space. Since the user >> controls the number of vmas, they can cause preempt_count to overflow. >> >> Fix by making mmu_take_all_locks() only disable preemption once by making >> the spinlocks preempt-neutral. >> > Right, so while this will get rid of the warning it doesn't make the > code any nicer, its still a massive !preempt latency spot. >
True. But this is a band-aid we can apply now while the correct fix is being worked out.
-- error compiling committee.c: too many arguments to function
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