Messages in this thread | | | Date | Fri, 6 Dec 2013 10:16:12 +1100 | From | Dave Chinner <> | Subject | Re: [OOPS, 3.13-rc2] null ptr in dio_complete() |
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On Fri, Dec 06, 2013 at 08:26:51AM +1100, Dave Chinner wrote: > On Thu, Dec 05, 2013 at 10:22:20PM +0800, Ming Lei wrote: > > On Wed, 4 Dec 2013 12:58:38 +1100 > > Dave Chinner <david@fromorbit.com> wrote: > > > > > > > > And I just hit this from running xfs_repair which is doing > > > multithreaded direct IO directly on /dev/vdc: > ..... > > > So this is looking like another virtio+blk_mq problem.... > > > > This one might be caused by using-after-'free' request because the freed > > request may be allocated to another CPU immediately, and the below patch > > may be helpful, would you mind testing it? > > > > diff --git a/block/blk-mq.c b/block/blk-mq.c > > index 6875736..2358bdf 100644 > > --- a/block/blk-mq.c > > +++ b/block/blk-mq.c > > @@ -311,12 +311,12 @@ void blk_mq_complete_request(struct request *rq, int error) > > > > blk_account_io_completion(rq, bytes); > > > > + blk_account_io_done(rq); > > + > > if (rq->end_io) > > rq->end_io(rq, error); > > else > > blk_mq_free_request(rq); > > - > > - blk_account_io_done(rq); > > } > > > > void __blk_mq_end_io(struct request *rq, int error) > > Testing it now. I'll let you know how it goes in couple of hours.
Ok, this looks like it is working correctly. The read/write io stats are now working properly, too. Thanks for finding the problem quickly!
Cheers,
Dave. -- Dave Chinner david@fromorbit.com
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