From: Jan Höppner Date: Fri, 9 Jun 2023 15:37:50 +0000 (+0200) Subject: s390/dasd: Use correct lock while counting channel queue length X-Git-Tag: v6.4-rc6~6^2 X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=ccc45cb4e7271c74dbb27776ae8f73d84557f5c6;p=tomoyo%2Ftomoyo-test1.git s390/dasd: Use correct lock while counting channel queue length The lock around counting the channel queue length in the BIODASDINFO ioctl was incorrectly changed to the dasd_block->queue_lock with commit 583d6535cb9d ("dasd: remove dead code"). This can lead to endless list iterations and a subsequent crash. The queue_lock is supposed to be used only for queue lists belonging to dasd_block. For dasd_device related queue lists the ccwdev lock must be used. Fix the mentioned issues by correctly using the ccwdev lock instead of the queue lock. Fixes: 583d6535cb9d ("dasd: remove dead code") Cc: stable@vger.kernel.org # v5.0+ Signed-off-by: Jan Höppner Reviewed-by: Stefan Haberland Signed-off-by: Stefan Haberland Link: https://lore.kernel.org/r/20230609153750.1258763-2-sth@linux.ibm.com Signed-off-by: Jens Axboe --- diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c index 9327dcdd6e5e..8fca725b3dae 100644 --- a/drivers/s390/block/dasd_ioctl.c +++ b/drivers/s390/block/dasd_ioctl.c @@ -552,10 +552,10 @@ static int __dasd_ioctl_information(struct dasd_block *block, memcpy(dasd_info->type, base->discipline->name, 4); - spin_lock_irqsave(&block->queue_lock, flags); + spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags); list_for_each(l, &base->ccw_queue) dasd_info->chanq_len++; - spin_unlock_irqrestore(&block->queue_lock, flags); + spin_unlock_irqrestore(get_ccwdev_lock(base->cdev), flags); return 0; }