From: Jan Höppner <hoeppner@xxxxxxxxxxxxx>
commit ccc45cb4e7271c74dbb27776ae8f73d84557f5c6 upstream.
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@xxxxxxxxxxxxxxx # v5.0+
Signed-off-by: Jan Höppner <hoeppner@xxxxxxxxxxxxx>
Reviewed-by: Stefan Haberland <sth@xxxxxxxxxxxxx>
Signed-off-by: Stefan Haberland <sth@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230609153750.1258763-2-sth@xxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/s390/block/dasd_ioctl.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -552,10 +552,10 @@ static int __dasd_ioctl_information(stru
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;
}
