Re: [PATCH] aio: ensure access to ctx->ring_pages is correctly serialised

[Benjamin LaHaise]

Hi Sasha,

On Tue, Mar 25, 2014 at 01:47:40PM -0400, Sasha Levin wrote:
> On 03/24/2014 03:07 PM, Benjamin LaHaise wrote:
...
> >Yeah, that's a problem -- thanks for the report.  The ring_lock mutex can't
> >be nested inside of mmap_sem, as aio_read_events_ring() can take a page
> >fault while holding ring_mutex.  That makes the following change required.
> >I'll fold this change into the patch that caused this issue.
> 
> Yup, that does the trick.
> 
> Could you please add something to document why this is a trylock instead of 
> a lock? If
> I were reading the code there's no way I'd understand what's the reason 
> behind it
> without knowing of this bug report.

Done.  I've updated the patch in my aio-next.git tree, so it should be in 
tomorrow's linux-next, and will give it one last day for any further problem 
reports.  Thanks for testing!

		-ben

> Thanks,
> Sasha

-- 
"Thought is the essence of where you are now."
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