lkml.org 
[lkml]   [2016]   [Aug]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] bdev: fix NULL pointer dereference in sync()/close() race
Hello,

On Sat, Aug 27, 2016 at 11:30:22AM +0200, Vegard Nossum wrote:
> > Don't know what's the right fix, but I posted a slightly different one
> > for the same crash some months ago:
> > https://patchwork.kernel.org/patch/8556941/
> >
>
> Ah, I'm sorry, I didn't see that.
>
> Your patch is 100% identical to my first attempt at a fix and I can
> confirm that it also fixes the problem for me.
>
> If people who are more savvy in block/fs code could ack the locking bits
> I think we should apply the patch ASAP because it's an easy local DOS if
> you have (open/read) access to any block device.

I think the right thing to do there is doing blkdev_get() /
blkdev_put() around func() invocation in iterate_bdevs() rather than
holding bd_mutex across the callback. Can you please verify whether
that works?

Thanks.

--
tejun

\
 
 \ /
  Last update: 2016-09-17 09:58    [W:1.147 / U:0.172 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site