The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x ccc45cb4e7271c74dbb27776ae8f73d84557f5c6 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023061111-tracing-shakiness-9054@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ccc45cb4e7271c74dbb27776ae8f73d84557f5c6 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jan=20H=C3=B6ppner?= hoeppner@linux.ibm.com Date: Fri, 9 Jun 2023 17:37:50 +0200 Subject: [PATCH] s390/dasd: Use correct lock while counting channel queue length MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

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 hoeppner@linux.ibm.com Reviewed-by: Stefan Haberland sth@linux.ibm.com Signed-off-by: Stefan Haberland sth@linux.ibm.com Link: https://lore.kernel.org/r/20230609153750.1258763-2-sth@linux.ibm.com Signed-off-by: Jens Axboe axboe@kernel.dk

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; }