====================================================== WARNING: possible circular locking dependency detected 4.14.280-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/11222 is trying to acquire lock: (&xt[i].mutex){+.+.}, at: [] target_revfn+0x43/0x210 net/netfilter/x_tables.c:354 but task is already holding lock: (&table[i].mutex){+.+.}, at: [] nfnl_lock net/netfilter/nfnetlink.c:61 [inline] (&table[i].mutex){+.+.}, at: [] 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 unregister_netdevice_many.part.0+0x18/0x2e0 net/core/dev.c:8293 unregister_netdevice_many+0x36/0x50 net/core/dev.c:8292 ip6gre_exit_net+0x41e/0x570 net/ipv6/ip6_gre.c:1209 ops_exit_list+0xad/0x160 net/core/net_namespace.c:142 cleanup_net+0x3b3/0x840 net/core/net_namespace.c:487 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 FAT-fs (loop4): bogus number of reserved sectors kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 -> #1 FAT-fs (loop4): Can't find a valid FAT filesystem (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:2454 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.1/11222: #0: (&table[i].mutex){+.+.}, at: [] nfnl_lock net/netfilter/nfnetlink.c:61 [inline] #0: (&table[i].mutex){+.+.}, at: [] nfnetlink_rcv_msg+0x726/0xc00 net/netfilter/nfnetlink.c:209 stack backtrace: CPU: 0 PID: 11222 Comm: syz-executor.1 Not tainted 4.14.280-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:2454 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: 0033:0x7f016e6a90e9 RSP: 002b:00007f016d01e168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f016e7bbf60 RCX: 00007f016e6a90e9 RDX: 0000000000000000 RSI: 0000000020000700 RDI: 0000000000000003 RBP: 00007f016e70308d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdfeaf0faf R14: 00007f016d01e300 R15: 0000000000022000 print_req_error: I/O error, dev loop4, sector 0 L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details. print_req_error: I/O error, dev loop4, sector 0 audit: type=1326 audit(1652941000.242:2): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=11396 comm="syz-executor.4" exe="/root/syz-executor.4" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7fcb8e0600e9 code=0x0 audit: type=1800 audit(1652941000.442:3): pid=11489 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="file0" dev="sda1" ino=14211 res=0 capability: warning: `syz-executor.4' uses deprecated v2 capabilities in a way that may be insecure unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1