diff options
| author | Bart Van Assche <bvanassche@acm.org> | 2012-06-29 15:33:22 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-08-09 08:31:28 -0700 |
| commit | bb0f467989fd14bd4bf41b9a30b49900f9223e47 (patch) | |
| tree | f207a35fabf30882f139e7c56877e66dd9f1a5c1 /drivers/scsi/scsi_lib.c | |
| parent | f07d3f59e35eb0fc8847587f601f84b8cfa8dd38 (diff) | |
SCSI: Fix device removal NULL pointer dereference
commit 67bd94130015c507011af37858989b199c52e1de upstream.
Use blk_queue_dead() to test whether the queue is dead instead
of !sdev. Since scsi_prep_fn() may be invoked concurrently with
__scsi_remove_device(), keep the queuedata (sdev) pointer in
__scsi_remove_device(). This patch fixes a kernel oops that
can be triggered by USB device removal. See also
http://www.spinics.net/lists/linux-scsi/msg56254.html.
Other changes included in this patch:
- Swap the blk_cleanup_queue() and kfree() calls in
scsi_host_dev_release() to make that code easier to grasp.
- Remove the queue dead check from scsi_run_queue() since the
queue state can change anyway at any point in that function
where the queue lock is not held.
- Remove the queue dead check from the start of scsi_request_fn()
since it is redundant with the scsi_device_online() check.
Reported-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/scsi/scsi_lib.c')
| -rw-r--r-- | drivers/scsi/scsi_lib.c | 32 |
1 files changed, 4 insertions, 28 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 4037fd5b1e0..f97edb75e56 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -406,10 +406,6 @@ static void scsi_run_queue(struct request_queue *q) 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); @@ -1370,16 +1366,16 @@ static inline int scsi_host_queue_ready(struct request_queue *q, * may be changed after request stacking drivers call the function, * regardless of taking lock or not. * - * When scsi can't dispatch I/Os anymore and needs to kill I/Os - * (e.g. !sdev), scsi needs to return 'not busy'. - * Otherwise, request stacking drivers may hold requests forever. + * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi + * needs to return 'not busy'. Otherwise, request stacking drivers + * may hold requests forever. */ static int scsi_lld_busy(struct request_queue *q) { struct scsi_device *sdev = q->queuedata; struct Scsi_Host *shost; - if (!sdev) + if (blk_queue_dead(q)) return 0; shost = sdev->host; @@ -1490,12 +1486,6 @@ static void scsi_request_fn(struct request_queue *q) struct scsi_cmnd *cmd; struct request *req; - if (!sdev) { - while ((req = blk_peek_request(q)) != NULL) - scsi_kill_request(req, q); - return; - } - if(!get_device(&sdev->sdev_gendev)) /* We must be tearing the block queue down already */ return; @@ -1697,20 +1687,6 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) return q; } -void scsi_free_queue(struct request_queue *q) -{ - unsigned long flags; - - WARN_ON(q->queuedata); - - /* cause scsi_request_fn() to kill all non-finished requests */ - spin_lock_irqsave(q->queue_lock, flags); - q->request_fn(q); - spin_unlock_irqrestore(q->queue_lock, flags); - - blk_cleanup_queue(q); -} - /* * Function: scsi_block_requests() * |