sshd (4439) used greatest stack depth: 16424 bytes left ================================================ WARNING: lock held when returning to user space! 4.16.0+ #3 Not tainted ------------------------------------------------ syzkaller749245/4455 is leaving the kernel with locks still held! 1 lock held by syzkaller749245/4455: #0: 00000000bbe08678 (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x1ec0 drivers/block/loop.c:1363