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Subject: Re: [RFT PATCH] blkio: alloc per cpu data from worker thread context( Re: kvm deadlock)
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From: Nate Custer <nate@cpanel.net>
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Date: Sun, 18 Dec 2011 15:25:48 -0600
Cc: Jens Axboe <axboe@kernel.dk>, Avi Kivity <avi@redhat.com>,
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To: Vivek Goyal <vgoyal@redhat.com>
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On Dec 16, 2011, at 2:29 PM, Vivek Goyal wrote:
> Thanks for testing it Nate. I did some debugging and found out that patch
> is doing double free on per cpu pointer hence the crash you are running
> into. I could reproduce this problem on my box. It is just a matter of
> doing rmdir on the blkio cgroup.
> 
> I understood the cmpxchg() semantics wrong. I have fixed it now and
> no crashes on directory removal. Can you please give this version a
> try.
> 
> Thanks
> Vivek

After 24 hours of stress testing the machine remains up and working without issue. I will continue to test it, but am reasonably confident that this patch resolves my issue.

Nate Custer