syzbot

audit: type=1326 audit(1627851708.050:18): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=10506 comm="syz-executor.3" exe="/root/syz-executor.3" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4665e9 code=0x0
======================================================
WARNING: possible circular locking dependency detected
4.14.241-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.3/10571 is trying to acquire lock:
 (&xt[i].mutex){+.+.}, at: [<ffffffff85f0cbf3>] match_revfn+0x43/0x210 net/netfilter/x_tables.c:332

but task is already holding lock:
 (&table[i].mutex){+.+.}, at: [<ffffffff85e38b16>] nfnl_lock net/netfilter/nfnetlink.c:61 [inline]
 (&table[i].mutex){+.+.}, at: [<ffffffff85e38b16>] 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+0x765/0xba0 net/core/dev.c:7210
       rollback_registered+0xca/0x170 net/core/dev.c:7252
       unregister_netdevice_queue+0x1b4/0x360 net/core/dev.c:8273
       br_del_bridge+0xa9/0xe0 net/bridge/br_if.c:419
       br_ioctl_deviceless_stub+0x1ff/0x5f0 net/bridge/br_ioctl.c:380
       sock_ioctl+0x254/0x4c0 net/socket.c:1038
       vfs_ioctl fs/ioctl.c:46 [inline]
       file_ioctl fs/ioctl.c:500 [inline]
       do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
       SYSC_ioctl fs/ioctl.c:701 [inline]
       SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
       do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
       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:684
       __do_replace+0x38d/0x580 net/ipv6/netfilter/ip6_tables.c:1105
       do_replace net/ipv6/netfilter/ip6_tables.c:1161 [inline]
       do_ip6t_set_ctl+0x256/0x3b0 net/ipv6/netfilter/ip6_tables.c:1687
       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
       udpv6_setsockopt+0x45/0x80 net/ipv6/udp.c:1462
       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
       match_revfn+0x43/0x210 net/netfilter/x_tables.c:332
       xt_find_revision+0x8d/0x1d0 net/netfilter/x_tables.c:380
       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:2435
       nfnetlink_rcv+0x1ab/0x1da0 net/netfilter/nfnetlink.c:515
       netlink_unicast_kernel net/netlink/af_netlink.c:1289 [inline]
       netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1315
       netlink_sendmsg+0x62e/0xb80 net/netlink/af_netlink.c:1880
       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.3/10571:
 #0:  (&table[i].mutex){+.+.}, at: [<ffffffff85e38b16>] nfnl_lock net/netfilter/nfnetlink.c:61 [inline]
 #0:  (&table[i].mutex){+.+.}, at: [<ffffffff85e38b16>] nfnetlink_rcv_msg+0x726/0xc00 net/netfilter/nfnetlink.c:209

stack backtrace:
CPU: 1 PID: 10571 Comm: syz-executor.3 Not tainted 4.14.241-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
 match_revfn+0x43/0x210 net/netfilter/x_tables.c:332
 xt_find_revision+0x8d/0x1d0 net/netfilter/x_tables.c:380
 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:2435
 nfnetlink_rcv+0x1ab/0x1da0 net/netfilter/nfnetlink.c:515
 netlink_unicast_kernel net/netlink/af_netlink.c:1289 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1315
 netlink_sendmsg+0x62e/0xb80 net/netlink/af_netlink.c:1880
 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: 0033:0x4665e9
RSP: 002b:00007f5702fb6188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
RDX: 0000000000000000 RSI: 00000000200016c0 RDI: 0000000000000003
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffe8d8a6a6f R14: 00007f5702fb6300 R15: 0000000000022000
binder: 11020:11025 ioctl c018620c 0 returned -22
binder: 11020:11033 ioctl c018620c 0 returned -22
binder: 11212:11219 ioctl c018620c 20000480 returned -22
binder: 11212:11243 ioctl c018620c 20000480 returned -22
binder: 11328:11333 ioctl c0306201 200003c0 returned -22
binder: 11332:11337 ioctl c0306201 0 returned -14
binder: 11328:11344 ioctl c0306201 200003c0 returned -22
IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready
WARNING: can't dereference registers at 0000000000000be0 for ip entry_SYSCALL_64_after_hwframe+0x46/0xbb
IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready
nvme_fabrics: unknown parameter or missing value '' in ctrl creation request
nvme_fabrics: unknown parameter or missing value '' in ctrl creation request
nvme_fabrics: unknown parameter or missing value '' in ctrl creation request
nvme_fabrics: unknown parameter or missing value '' in ctrl creation request