MTD: Attempt to mount non-MTD device "/dev/loop2"
romfs: Mounting image 'rom 5f663c08' through the block layer
======================================================
WARNING: possible circular locking dependency detected
4.14.277-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.5/11355 is trying to acquire lock:
 (&xt[i].mutex){+.+.}, at: [<ffffffff85f1c7d3>] target_revfn+0x43/0x210 net/netfilter/x_tables.c:354

but task is already holding lock:
 (&table[i].mutex){+.+.}, at: [<ffffffff85e48996>] nfnl_lock net/netfilter/nfnetlink.c:61 [inline]
 (&table[i].mutex){+.+.}, at: [<ffffffff85e48996>] nfnetlink_rcv_msg+0x726/0xc00 net/netfilter/nfnetlink.c:209

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&table[i].mutex){+.+.}:
       __mutex_lock_common kernel/locking/mutex.c:756 [inline]
       __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893
       nf_tables_netdev_event+0x10d/0x4d0 net/netfilter/nf_tables_netdev.c:122
       notifier_call_chain+0x108/0x1a0 kernel/notifier.c:93
       call_netdevice_notifiers_info net/core/dev.c:1667 [inline]
       call_netdevice_notifiers net/core/dev.c:1683 [inline]
       rollback_registered_many+0x765/0xbb0 net/core/dev.c:7211
       rollback_registered+0xca/0x170 net/core/dev.c:7253
       unregister_netdevice_queue+0x1b4/0x360 net/core/dev.c:8274
       unregister_netdevice include/linux/netdevice.h:2444 [inline]
       __tun_detach+0xca2/0xf60 drivers/net/tun.c:584
       tun_detach drivers/net/tun.c:594 [inline]
       tun_chr_close+0x41/0x60 drivers/net/tun.c:2732
       __fput+0x25f/0x7a0 fs/file_table.c:210
       task_work_run+0x11f/0x190 kernel/task_work.c:113
       tracehook_notify_resume include/linux/tracehook.h:191 [inline]
       exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
       prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
       syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
       do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
       entry_SYSCALL_64_after_hwframe+0x46/0xbb

-> #1 (rtnl_mutex){+.+.}:
       __mutex_lock_common kernel/locking/mutex.c:756 [inline]
       __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893
       unregister_netdevice_notifier+0x5e/0x2b0 net/core/dev.c:1630
       tee_tg_destroy+0x5c/0xb0 net/netfilter/xt_TEE.c:123
       cleanup_entry+0x232/0x310 net/ipv6/netfilter/ip6_tables.c:685
       __do_replace+0x38d/0x580 net/ipv6/netfilter/ip6_tables.c:1106
       do_replace net/ipv6/netfilter/ip6_tables.c:1162 [inline]
       do_ip6t_set_ctl+0x256/0x3b0 net/ipv6/netfilter/ip6_tables.c:1688
       nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
       nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115
       ipv6_setsockopt+0xc0/0x120 net/ipv6/ipv6_sockglue.c:937
       tcp_setsockopt+0x7b/0xc0 net/ipv4/tcp.c:2830
       SYSC_setsockopt net/socket.c:1865 [inline]
       SyS_setsockopt+0x110/0x1e0 net/socket.c:1844
       do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
       entry_SYSCALL_64_after_hwframe+0x46/0xbb

-> #0 (&xt[i].mutex){+.+.}:
       lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
       __mutex_lock_common kernel/locking/mutex.c:756 [inline]
       __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893
       target_revfn+0x43/0x210 net/netfilter/x_tables.c:354
       xt_find_revision+0x15e/0x1d0 net/netfilter/x_tables.c:378
       nfnl_compat_get+0x1f7/0x870 net/netfilter/nft_compat.c:678
       nfnetlink_rcv_msg+0x9bb/0xc00 net/netfilter/nfnetlink.c:214
       netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2455
       nfnetlink_rcv+0x1ab/0x1da0 net/netfilter/nfnetlink.c:515
       netlink_unicast_kernel net/netlink/af_netlink.c:1296 [inline]
       netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1322
       netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1893
       sock_sendmsg_nosec net/socket.c:646 [inline]
       sock_sendmsg+0xb5/0x100 net/socket.c:656
       ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
       __sys_sendmsg+0xa3/0x120 net/socket.c:2096
       SYSC_sendmsg net/socket.c:2107 [inline]
       SyS_sendmsg+0x27/0x40 net/socket.c:2103
       do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
       entry_SYSCALL_64_after_hwframe+0x46/0xbb

other info that might help us debug this:

Chain exists of:
  &xt[i].mutex --> rtnl_mutex --> &table[i].mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&table[i].mutex);
                               lock(rtnl_mutex);
                               lock(&table[i].mutex);
  lock(&xt[i].mutex);

 *** DEADLOCK ***

1 lock held by syz-executor.5/11355:
 #0:  (&table[i].mutex){+.+.}, at: [<ffffffff85e48996>] nfnl_lock net/netfilter/nfnetlink.c:61 [inline]
 #0:  (&table[i].mutex){+.+.}, at: [<ffffffff85e48996>] nfnetlink_rcv_msg+0x726/0xc00 net/netfilter/nfnetlink.c:209

stack backtrace:
CPU: 0 PID: 11355 Comm: syz-executor.5 Not tainted 4.14.277-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258
 check_prev_add kernel/locking/lockdep.c:1905 [inline]
 check_prevs_add kernel/locking/lockdep.c:2022 [inline]
 validate_chain kernel/locking/lockdep.c:2464 [inline]
 __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491
 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
 __mutex_lock_common kernel/locking/mutex.c:756 [inline]
 __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893
 target_revfn+0x43/0x210 net/netfilter/x_tables.c:354
 xt_find_revision+0x15e/0x1d0 net/netfilter/x_tables.c:378
 nfnl_compat_get+0x1f7/0x870 net/netfilter/nft_compat.c:678
 nfnetlink_rcv_msg+0x9bb/0xc00 net/netfilter/nfnetlink.c:214
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2455
 nfnetlink_rcv+0x1ab/0x1da0 net/netfilter/nfnetlink.c:515
 netlink_unicast_kernel net/netlink/af_netlink.c:1296 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1322
 netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1893
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f8d570010e9
RSP: 002b:00007f8d55976168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8d57113f60 RCX: 00007f8d570010e9
RDX: 0000000000000084 RSI: 0000000020000280 RDI: 0000000000000003
RBP: 00007f8d5705b08d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc4c7def9f R14: 00007f8d55976300 R15: 0000000000022000
libceph: mon1 [::6]:6789 socket closed (con state CONNECTING)
ceph: No mds server is up or the cluster is laggy
ceph: No mds server is up or the cluster is laggy
ceph: No mds server is up or the cluster is laggy
hub 9-0:1.0: USB hub found
hub 9-0:1.0: 8 ports detected
unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1
hub 9-0:1.0: USB hub found
hub 9-0:1.0: 8 ports detected
hub 9-0:1.0: USB hub found
hub 9-0:1.0: 8 ports detected
hub 9-0:1.0: USB hub found
hub 9-0:1.0: 8 ports detected
hub 9-0:1.0: USB hub found
hub 9-0:1.0: 8 ports detected
hfs: invalid uid -1
hfs: unable to parse mount options
hub 9-0:1.0: USB hub found
hub 9-0:1.0: 8 ports detected
EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue
EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue
EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue
EXT4-fs (loop1): mounted filesystem without journal. Opts: ,errors=continue
audit: type=1804 audit(1651664988.807:26): pid=11910 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.4" name="/root/syzkaller-testdir1590308703/syzkaller.0vDOAt/85/bus" dev="sda1" ino=14241 res=1
EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue
audit: type=1804 audit(1651664988.937:27): pid=11919 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.4" name="/root/syzkaller-testdir1590308703/syzkaller.0vDOAt/86/bus" dev="sda1" ino=14177 res=1
audit: type=1804 audit(1651664989.027:28): pid=11931 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.4" name="/root/syzkaller-testdir1590308703/syzkaller.0vDOAt/87/bus" dev="sda1" ino=14249 res=1
EXT4-fs (loop1): mounted filesystem without journal. Opts: ,errors=continue