IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready ====================================================== [ INFO: possible circular locking dependency detected ] 4.9.105-gd7e64f8 #40 Not tainted ------------------------------------------------------- syz-executor124/3795 is trying to acquire lock: (sk_lock-AF_INET){+.+.+.}, at: [] lock_sock include/net/sock.h:1404 [inline] (sk_lock-AF_INET){+.+.+.}, at: [] set_mcast_if net/netfilter/ipvs/ip_vs_sync.c:1370 [inline] (sk_lock-AF_INET){+.+.+.}, at: [] make_send_sock net/netfilter/ipvs/ip_vs_sync.c:1490 [inline] (sk_lock-AF_INET){+.+.+.}, at: [] start_sync_thread+0x88b/0x1e80 net/netfilter/ipvs/ip_vs_sync.c:1885 but task is already holding lock: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 __mutex_lock_common kernel/locking/mutex.c:521 [inline] mutex_lock_nested+0xc0/0x870 kernel/locking/mutex.c:621 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 mrtsock_destruct+0x3b/0x1e0 net/ipv4/ipmr.c:1231 ip_ra_control+0x2c2/0x420 net/ipv4/ip_sockglue.c:360 do_ip_setsockopt.isra.13+0x15ff/0x2b10 net/ipv4/ip_sockglue.c:1139 ip_setsockopt+0x3a/0xb0 net/ipv4/ip_sockglue.c:1242 raw_setsockopt+0xb7/0xd0 net/ipv4/raw.c:833 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2706 SYSC_setsockopt net/socket.c:1772 [inline] SyS_setsockopt+0x166/0x260 net/socket.c:1751 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 entry_SYSCALL_64_after_swapgs+0x5d/0xdb check_prev_add kernel/locking/lockdep.c:1828 [inline] check_prevs_add kernel/locking/lockdep.c:1938 [inline] validate_chain kernel/locking/lockdep.c:2265 [inline] __lock_acquire+0x3019/0x4070 kernel/locking/lockdep.c:3345 lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 lock_sock_nested+0xc6/0x120 net/core/sock.c:2511 lock_sock include/net/sock.h:1404 [inline] set_mcast_if net/netfilter/ipvs/ip_vs_sync.c:1370 [inline] make_send_sock net/netfilter/ipvs/ip_vs_sync.c:1490 [inline] start_sync_thread+0x88b/0x1e80 net/netfilter/ipvs/ip_vs_sync.c:1885 do_ip_vs_set_ctl+0x90f/0xbb0 net/netfilter/ipvs/ip_vs_ctl.c:2396 nf_sockopt net/netfilter/nf_sockopt.c:105 [inline] nf_setsockopt+0x6d/0xc0 net/netfilter/nf_sockopt.c:114 ip_setsockopt+0x9a/0xb0 net/ipv4/ip_sockglue.c:1249 udp_setsockopt+0x4a/0x90 net/ipv4/udp.c:2091 ipv6_setsockopt+0x10a/0x130 net/ipv6/ipv6_sockglue.c:901 tcp_setsockopt+0x88/0xe0 net/ipv4/tcp.c:2758 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2706 SYSC_setsockopt net/socket.c:1772 [inline] SyS_setsockopt+0x166/0x260 net/socket.c:1751 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 entry_SYSCALL_64_after_swapgs+0x5d/0xdb other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock(sk_lock-AF_INET); lock(rtnl_mutex); lock(sk_lock-AF_INET); *** DEADLOCK *** 2 locks held by syz-executor124/3795: #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 #1: (ipvs->sync_mutex){+.+.+.}, at: [] start_sync_thread+0x118/0x1e80 net/netfilter/ipvs/ip_vs_sync.c:1779 stack backtrace: CPU: 0 PID: 3795 Comm: syz-executor124 Not tainted 4.9.105-gd7e64f8 #40 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d9747538 ffffffff81eb41a9 ffffffff855e7690 ffffffff8559cf30 ffffffff855e7690 ffff8801b752a0e8 ffff8801b7529800 ffff8801d9747580 ffffffff8142679d 0000000000000001 00000000b7529800 0000000000000001 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] print_circular_bug.cold.51+0x1bd/0x27d kernel/locking/lockdep.c:1202 [] check_prev_add kernel/locking/lockdep.c:1828 [inline] [] check_prevs_add kernel/locking/lockdep.c:1938 [inline] [] validate_chain kernel/locking/lockdep.c:2265 [inline] [] __lock_acquire+0x3019/0x4070 kernel/locking/lockdep.c:3345 [] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 [] lock_sock_nested+0xc6/0x120 net/core/sock.c:2511 [] lock_sock include/net/sock.h:1404 [inline] [] set_mcast_if net/netfilter/ipvs/ip_vs_sync.c:1370 [inline] [] make_send_sock net/netfilter/ipvs/ip_vs_sync.c:1490 [inline] [] start_sync_thread+0x88b/0x1e80 net/netfilter/ipvs/ip_vs_sync.c:1885 [] do_ip_vs_set_ctl+0x90f/0xbb0 net/netfilter/ipvs/ip_vs_ctl.c:2396 [] nf_sockopt net/netfilter/nf_sockopt.c:105 [inline] [] nf_setsockopt+0x6d/0xc0 net/netfilter/nf_sockopt.c:114 [] ip_setsockopt+0x9a/0xb0 net/ipv4/ip_sockglue.c:1249 [] udp_setsockopt+0x4a/0x90 net/ipv4/udp.c:2091 [] ipv6_setsockopt+0x10a/0x130 net/ipv6/ipv6_sockglue.c:901 [] tcp_setsockopt+0x88/0xe0 net/ipv4/tcp.c:2758 [] sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2706 [] SYSC_setsockopt net/socket.c:1772 [inline] [] SyS_setsockopt+0x166/0x260 net/socket.c:1751 [] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb IPVS: sync thread started: state = MASTER, mcast_ifn = veth0_to_bridge, syncid = 3, id = 0