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WARNING: lock held when returning to user space!
4.14.301-syzkaller #0 Not tainted
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syz-executor.0/31986 is leaving the kernel with locks still held!
1 lock held by syz-executor.0/31986:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffff838ddff7>] lo_ioctl+0x87/0x1cd0 drivers/block/loop.c:1419