On (24/10/16 21:35), Ming Lei wrote: > On Wed, Oct 09, 2024 at 01:38:20PM +0200, Christoph Hellwig wrote: > > When del_gendisk shuts down access to a gendisk, it could lead to a > > deadlock with sd or, which try to submit passthrough SCSI commands from > > their ->release method under open_mutex. The submission can be blocked > > in blk_enter_queue while del_gendisk can't get to actually telling them > > top stop and wake them up. > > When ->release() waits in blk_enter_queue(), the following code block > > mutex_lock(&disk->open_mutex); > __blk_mark_disk_dead(disk); > xa_for_each_start(&disk->part_tbl, idx, part, 1) > drop_partition(part); > mutex_unlock(&disk->open_mutex); blk_enter_queue()->schedule() holds ->open_mutex, so that block of code sleeps on ->open_mutex. We can't drain under ->open_mutex.
