Re: [PATCH] blk-mq: Avoid race condition with uninitialized requests

[Jens Axboe]

On 2014-09-22 08:15, Christian Borntraeger wrote:
> On 09/18/2014 11:04 AM, David Hildenbrand wrote:
> > This patch should fix the bug reported in https://lkml.org/lkml/2014/9/11/249.
> >
> > We have to initialize at least the atomic_flags and the cmd_flags when
> > allocating storage for the requests.
> >
> > Otherwise blk_mq_timeout_check() might dereference uninitialized pointers when
> > racing with the creation of a request.
> >
> > Also move the reset of cmd_flags for the initializing code to the point where a
> > request is freed. So we will never end up with pending flush request indicators
> > that might trigger dereferences of invalid pointers in blk_mq_timeout_check().
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
>
> Acked-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>
> Can you please add
> Reported-by: Paulo De Rezende Pinatti <ppinatti@xxxxxxxxxxxxxxxxxx>
> Tested-by: Paulo De Rezende Pinatti <ppinatti@xxxxxxxxxxxxxxxxxx>
>
> as Paulo did the testing work?
>
> We thing this patch is fine and should go upstream.

I might have to pick'n rebase the series, in which case I'll add it. But 
I already queued it up last week, so if I don't, then I can't easily add 
it. I wish the git notes wasn't such a horrible and unusable hack, so we 
had a chance to annotate commits without having to rewrite history...

--
Jens Axboe

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