================================================
WARNING: lock held when returning to user space!
4.14.295-syzkaller #0 Not tainted
------------------------------------------------
syz-executor.0/18949 is leaving the kernel with locks still held!
1 lock held by syz-executor.0/18949:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffff838da087>] lo_ioctl+0x87/0x1cd0 drivers/block/loop.c:1419