This is a note to let you know that I've just added the patch titled scsi: core: Cap scsi_host cmd_per_lun at can_queue to the 5.13-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-core-cap-scsi_host-cmd_per_lun-at-can_queue.patch and it can be found in the queue-5.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 999954bc56a1de02f3510207d99e0b39ca7eb527 Author: John Garry <john.garry@xxxxxxxxxx> Date: Wed May 19 22:31:02 2021 +0800 scsi: core: Cap scsi_host cmd_per_lun at can_queue [ Upstream commit ea2f0f77538c50739b9fb4de4700cee5535e1f77 ] The sysfs handling function sdev_store_queue_depth() enforces that the sdev queue depth cannot exceed shost can_queue. The initial sdev queue depth comes from shost cmd_per_lun. However, the LLDD may manually set cmd_per_lun to be larger than can_queue, which leads to an initial sdev queue depth greater than can_queue. Such an issue was reported in [0], which caused a hang. That has since been fixed in commit fc09acb7de31 ("scsi: scsi_debug: Fix cmd_per_lun, set to max_queue"). Stop this possibly happening for other drivers by capping shost cmd_per_lun at shost can_queue. [0] https://lore.kernel.org/linux-scsi/YHaez6iN2HHYxYOh@T590/ Link: https://lore.kernel.org/r/1621434662-173079-1-git-send-email-john.garry@xxxxxxxxxx Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx> Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx> Signed-off-by: John Garry <john.garry@xxxxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index 00ec0b9e9dbb..b40bb6bd5f5d 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -220,6 +220,9 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev, goto fail; } + shost->cmd_per_lun = min_t(short, shost->cmd_per_lun, + shost->can_queue); + error = scsi_init_sense_cache(shost); if (error) goto fail;