Patch "scsi: avoid a permanent stop of the scsi device's request queue" has been added to the 4.4-stable tree

Patch "scsi: avoid a permanent stop of the scsi device's request queue" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    scsi: avoid a permanent stop of the scsi device's request queue

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     scsi-avoid-a-permanent-stop-of-the-scsi-device-s-request-queue.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d2a145252c52792bc59e4767b486b26c430af4bb Mon Sep 17 00:00:00 2001
From: Wei Fang <fangwei1@huawei.com>
Date: Tue, 13 Dec 2016 09:25:21 +0800
Subject: scsi: avoid a permanent stop of the scsi device's request queue

From: Wei Fang <fangwei1@huawei.com>

commit d2a145252c52792bc59e4767b486b26c430af4bb upstream.

A race between scanning and fc_remote_port_delete() may result in a
permanent stop if the device gets blocked before scsi_sysfs_add_sdev()
and unblocked after.  The reason is that blocking a device sets both the
SDEV_BLOCKED state and the QUEUE_FLAG_STOPPED.  However,
scsi_sysfs_add_sdev() unconditionally sets SDEV_RUNNING which causes the
device to be ignored by scsi_target_unblock() and thus never have its
QUEUE_FLAG_STOPPED cleared leading to a device which is apparently
running but has a stopped queue.

We actually have two places where SDEV_RUNNING is set: once in
scsi_add_lun() which respects the blocked flag and once in
scsi_sysfs_add_sdev() which doesn't.  Since the second set is entirely
spurious, simply remove it to fix the problem.

Reported-by: Zengxi Chen <chenzengxi@huawei.com>
Signed-off-by: Wei Fang <fangwei1@huawei.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/scsi/scsi_sysfs.c |    4 ----
 1 file changed, 4 deletions(-)

--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1031,10 +1031,6 @@ int scsi_sysfs_add_sdev(struct scsi_devi
 	struct request_queue *rq = sdev->request_queue;
 	struct scsi_target *starget = sdev->sdev_target;
 
-	error = scsi_device_set_state(sdev, SDEV_RUNNING);
-	if (error)
-		return error;
-
 	error = scsi_target_add(starget);
 	if (error)
 		return error;


Patches currently in stable-queue which might be from fangwei1@huawei.com are

queue-4.4/scsi-avoid-a-permanent-stop-of-the-scsi-device-s-request-queue.patch
queue-4.4/block-protect-iterate_bdevs-against-concurrent-close.patch