================================================
WARNING: lock held when returning to user space!
syzkaller #0 Not tainted
------------------------------------------------
syz.3.11/5907 is leaving the kernel with locks still held!
1 lock held by syz.3.11/5907:
 #0: ffff888021215b60 (&lo->lo_mutex){+.+.}-{3:3}, at: loop_set_block_size+0x7c/0x480 drivers/block/loop.c:1490
BTRFS info (device loop3): scrub: started on devid 1
BTRFS info (device loop3): scrub: finished on devid 1 with status: 0