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authorBart Van Assche <bart.vanassche@sandisk.com>2016-11-01 17:19:57 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2016-11-01 20:32:24 +0300
commitdf3d422cbac685da882e4c239dfda07de33d431b (patch)
tree5d61ed8c7e551eb980a4c1772964bdce25d8c1d8 /drivers/scsi/device_handler
parentaac173e9618faadf8f92af6cc05e64f7acc64d79 (diff)
downloadlinux-df3d422cbac685da882e4c239dfda07de33d431b.tar.xz
scsi: scsi_dh_alua: Fix a reference counting bug
The code at the end of alua_rtpg_work() is as follows: scsi_device_put(sdev); kref_put(&pg->kref, release_port_group); In other words, alua_rtpg_queue() must hold an sdev reference and a pg reference before queueing rtpg work. If no rtpg work is queued no additional references should be held when alua_rtpg_queue() returns. If no rtpg work is queued, ensure that alua_rtpg_queue() only gives up the sdev reference if that reference was obtained by the same alua_rtpg_queue() call. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reported-by: Tang Junhui <tang.junhui@zte.com.cn> Cc: Hannes Reinecke <hare@suse.com> Cc: Tang Junhui <tang.junhui@zte.com.cn> Cc: <stable@vger.kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/device_handler')
-rw-r--r--drivers/scsi/device_handler/scsi_dh_alua.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index f375167f16ea..7bb20684e9fa 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -891,6 +891,7 @@ static void alua_rtpg_queue(struct alua_port_group *pg,
/* Do not queue if the worker is already running */
if (!(pg->flags & ALUA_PG_RUNNING)) {
kref_get(&pg->kref);
+ sdev = NULL;
start_queue = 1;
}
}
@@ -902,7 +903,8 @@ static void alua_rtpg_queue(struct alua_port_group *pg,
if (start_queue &&
!queue_delayed_work(alua_wq, &pg->rtpg_work,
msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS))) {
- scsi_device_put(sdev);
+ if (sdev)
+ scsi_device_put(sdev);
kref_put(&pg->kref, release_port_group);
}
}