[SCSI] fix oops in scsi_run_queue()

The recent commit closing the race window in device teardown:

commit 86cbfb5607
Author: James Bottomley <James.Bottomley@suse.de>
Date:   Fri Apr 22 10:39:59 2011 -0500

    [SCSI] put stricter guards on queue dead checks

is causing a potential NULL deref in scsi_run_queue() because the
q->queuedata may already be NULL by the time this function is called.
Since we shouldn't be running a queue that is being torn down, simply
add a NULL check in scsi_run_queue() to forestall this.

Tested-by: Jim Schutt <jaschut@sandia.gov>
Cc: stable@kernel.org
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
This commit is contained in:
James Bottomley 2011-05-01 09:42:07 -05:00
parent 3fd9952df4
commit c055f5b261

View File

@ -400,10 +400,15 @@ static inline int scsi_host_is_busy(struct Scsi_Host *shost)
static void scsi_run_queue(struct request_queue *q)
{
struct scsi_device *sdev = q->queuedata;
struct Scsi_Host *shost = sdev->host;
struct Scsi_Host *shost;
LIST_HEAD(starved_list);
unsigned long flags;
/* if the device is dead, sdev will be NULL, so no queue to run */
if (!sdev)
return;
shost = sdev->host;
if (scsi_target(sdev)->single_lun)
scsi_single_lun_run(sdev);