From 625fe857e4fac6518716f3c0ff5e5deb8ec6d238 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 17 Mar 2017 17:02:01 -0700 Subject: [PATCH] scsi: scsi_dh_alua: Check scsi_device_get() return value Do not queue ALUA work nor call scsi_device_put() if the scsi_device_get() call fails. This patch fixes the following crash: general protection fault: 0000 [#1] SMP RIP: 0010:scsi_device_put+0xb/0x30 Call Trace: scsi_disk_put+0x2d/0x40 sd_release+0x3d/0xb0 __blkdev_put+0x29e/0x360 blkdev_put+0x49/0x170 dm_put_table_device+0x58/0xc0 [dm_mod] dm_put_device+0x70/0xc0 [dm_mod] free_priority_group+0x92/0xc0 [dm_multipath] free_multipath+0x70/0xc0 [dm_multipath] multipath_dtr+0x19/0x20 [dm_multipath] dm_table_destroy+0x67/0x120 [dm_mod] dev_suspend+0xde/0x240 [dm_mod] ctl_ioctl+0x1f5/0x520 [dm_mod] dm_ctl_ioctl+0xe/0x20 [dm_mod] do_vfs_ioctl+0x8f/0x700 SyS_ioctl+0x3c/0x70 entry_SYSCALL_64_fastpath+0x18/0xad Fixes: commit 03197b61c5ec ("scsi_dh_alua: Use workqueue for RTPG") Signed-off-by: Bart Van Assche Cc: Hannes Reinecke Cc: Tang Junhui Cc: Reviewed-by: Hannes Reinecke Signed-off-by: Martin K. Petersen --- drivers/scsi/device_handler/scsi_dh_alua.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index 48e200102221..e0b15f3dd303 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -870,7 +870,7 @@ static void alua_rtpg_queue(struct alua_port_group *pg, unsigned long flags; struct workqueue_struct *alua_wq = kaluad_wq; - if (!pg) + if (!pg || scsi_device_get(sdev)) return; spin_lock_irqsave(&pg->lock, flags); @@ -884,14 +884,12 @@ static void alua_rtpg_queue(struct alua_port_group *pg, pg->flags |= ALUA_PG_RUN_RTPG; kref_get(&pg->kref); pg->rtpg_sdev = sdev; - scsi_device_get(sdev); start_queue = 1; } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force) { pg->flags |= ALUA_PG_RUN_RTPG; /* Do not queue if the worker is already running */ if (!(pg->flags & ALUA_PG_RUNNING)) { kref_get(&pg->kref); - sdev = NULL; start_queue = 1; } } @@ -900,13 +898,15 @@ static void alua_rtpg_queue(struct alua_port_group *pg, alua_wq = kaluad_sync_wq; spin_unlock_irqrestore(&pg->lock, flags); - if (start_queue && - !queue_delayed_work(alua_wq, &pg->rtpg_work, - msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS))) { - if (sdev) - scsi_device_put(sdev); - kref_put(&pg->kref, release_port_group); + if (start_queue) { + if (queue_delayed_work(alua_wq, &pg->rtpg_work, + msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS))) + sdev = NULL; + else + kref_put(&pg->kref, release_port_group); } + if (sdev) + scsi_device_put(sdev); } /* -- 2.20.1