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>
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;
}