lkml.org 
[lkml]   [2017]   [May]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] scsi: sg: don't return bogus Sg_requests
From
Date
On 05/10/2017 09:41 AM, Johannes Thumshirn wrote:
> If the list search in sg_get_rq_mark() fails to find a valid request, we
> return a bogus element. This then can later lead to a GPF in sg_remove_scat().
>
> So don't return bogus Sg_requests in sg_get_rq_mark() but NULL in case the
> list search doesn't find a valid request.
>
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> Reported-by: Andrey Konovalov <andreyknvl@google.com>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Doug Gilbert <dgilbert@interlog.com>
> ---
> drivers/scsi/sg.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
> index 0a38ba01b7b4..abfde23fa186 100644
> --- a/drivers/scsi/sg.c
> +++ b/drivers/scsi/sg.c
> @@ -2078,7 +2078,7 @@ sg_get_rq_mark(Sg_fd * sfp, int pack_id)
> }
> }
> write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
> - return resp;
> + return (resp->done == 2) ? resp : NULL;
> }
>
> /* always adds to end of list */
>
Not quite.
Please return 'resp' directly from within the loop.
With this fix we run into the risk that by chance the uninitialized
'resp' pointer contains a '2' at the 'done' location, triggering this
issue again.

Cheers,

Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)

\
 
 \ /
  Last update: 2017-05-10 21:21    [W:0.034 / U:1.664 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site