================================================ WARNING: lock held when returning to user space! 4.14.298-syzkaller #0 Not tainted ------------------------------------------------ syz-executor.1/10009 is leaving the kernel with locks still held! 1 lock held by syz-executor.1/10009: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x87/0x1cd0 drivers/block/loop.c:1419 attempt to access beyond end of device loop3: rw=1, want=256, limit=64 unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1