lkml.org 
[lkml]   [2019]   [Nov]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] block: Replace bio_check_ro()'s WARN_ON()
On Fri, Nov 22, 2019 at 12:09:14PM -0700, Jens Axboe wrote:
> On 11/22/19 12:07 PM, Christoph Hellwig wrote:
> > On Fri, Nov 22, 2019 at 10:53:22AM -0800, Kees Cook wrote:
> >> Friendly ping! I keep tripping over this. Can this please get applied so
> >> we can silence syzbot and avoid needless WARNs? :)
> >
> > What call stack reaches this? Upper layers should never submit a write
> > bio on a read-only queue, and we need to fix that in the upper layer.
>
> It's an fsync, the trace is here:
>
> https://syzkaller.appspot.com/x/log.txt?x=159503d2e00000

Oh. I think this is a bug in the block layer, we should not treat
a sync as write for the purposes of is read-only checks, as it never
writes data to the device. At the request layer we alread use
the proper REQ_OP_FLUSH, but at the bio layer we are still abusing
empty writes apparently. I'll try to cook up something over the
weekend.

\
 
 \ /
  Last update: 2019-11-22 20:15    [W:0.139 / U:0.560 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site