================================================
WARNING: lock held when returning to user space!
5.5.0-rc6-syzkaller #0 Not tainted
------------------------------------------------
syz-executor.5/17983 is leaving the kernel with locks still held!
1 lock held by syz-executor.5/17983:
 #0: ffff8880a6498748 (&tfile->napi_mutex){+.+.}, at: tun_get_user+0x1604/0x3fc0 drivers/net/tun.c:1835