./strace-static-x86_64 -e \!wait4,clock_nanosleep,nanosleep -s 100 -x -f ./syz-executor3839188786 <...> DUID 00:04:ac:03:58:10:d0:76:5c:28:30:a7:8a:8b:4a:a3:06:e2 forked to background, child pid 4651 [ 36.388110][ T4652] 8021q: adding VLAN 0 to HW filter on device bond0 [ 36.416026][ T4652] eql: remember to turn off Van-Jacobson compression on your slave devices Starting sshd: OK syzkaller Warning: Permanently added '10.128.1.107' (ECDSA) to the list of known hosts. execve("./syz-executor3839188786", ["./syz-executor3839188786"], 0x7fffe9cff300 /* 10 vars */) = 0 brk(NULL) = 0x555556ba6000 brk(0x555556ba6c40) = 0x555556ba6c40 arch_prctl(ARCH_SET_FS, 0x555556ba6300) = 0 uname({sysname="Linux", nodename="syzkaller", ...}) = 0 readlink("/proc/self/exe", "/root/syz-executor3839188786", 4096) = 28 brk(0x555556bc7c40) = 0x555556bc7c40 brk(0x555556bc8000) = 0x555556bc8000 mprotect(0x7fcd4cb91000, 16384, PROT_READ) = 0 mmap(0x1ffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1ffff000 mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000 mmap(0x21000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x21000000 socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC) = 3 socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC) = 4 sendto(4, [{nlmsg_len=32, nlmsg_type=0x10 /* NLMSG_??? */, nlmsg_flags=NLM_F_REQUEST|NLM_F_ACK, nlmsg_seq=0, nlmsg_pid=0}, "\x03\x00\x00\x00\x09\x00\x02\x00\x6c\x32\x74\x70\x00\x00\x00\x00"], 32, 0, {sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, 12) = 32 recvfrom(4, [{nlmsg_len=276, nlmsg_type=nlctrl, nlmsg_flags=0, nlmsg_seq=0, nlmsg_pid=5077}, "\x01\x02\x00\x00\x09\x00\x02\x00\x6c\x32\x74\x70\x00\x00\x00\x00\x06\x00\x01\x00\x30\x00\x00\x00\x08\x00\x03\x00\x01\x00\x00\x00\x08\x00\x04\x00\x00\x00\x00\x00\x08\x00\x05\x00\x23\x00\x00\x00\xb8\x00\x06\x00\x14\x00\x01\x00\x08\x00\x01\x00\x00\x00\x00\x00\x08\x00\x02\x00\x0a\x00\x00\x00\x14\x00\x02\x00\x08\x00\x01\x00\x01\x00\x00\x00\x08\x00\x02\x00\x1a\x00\x00\x00\x14\x00\x03\x00\x08\x00\x01\x00"...], 4096, 0, NULL, NULL) = 276 recvfrom(4, [{nlmsg_len=36, nlmsg_type=NLMSG_ERROR, nlmsg_flags=NLM_F_CAPPED, nlmsg_seq=0, nlmsg_pid=5077}, {error=0, msg={nlmsg_len=32, nlmsg_type=nlctrl, nlmsg_flags=NLM_F_REQUEST|NLM_F_ACK, nlmsg_seq=0, nlmsg_pid=0}}], 4096, 0, NULL, NULL) = 36 close(4) = 0 socket(AF_INET, SOCK_DGRAM, IPPROTO_IP) = 4 syzkaller login: [ 56.810634][ T5077] [ 56.813001][ T5077] ====================================================== [ 56.820088][ T5077] WARNING: possible circular locking dependency detected [ 56.827086][ T5077] 6.2.0-rc4-next-20230117-syzkaller #0 Not tainted [ 56.833566][ T5077] ------------------------------------------------------ [ 56.840561][ T5077] syz-executor383/5077 is trying to acquire lock: [ 56.846955][ T5077] ffff888017e10f30 (slock-AF_INET){+.-.}-{2:2}, at: release_sock+0x1f/0x1b0 [ 56.855673][ T5077] [ 56.855673][ T5077] but task is already holding lock: [ 56.863014][ T5077] ffff888017e11238 (clock-AF_INET){++..}-{2:2}, at: l2tp_tunnel_register+0x1c3/0xd80 [ 56.872480][ T5077] [ 56.872480][ T5077] which lock already depends on the new lock. [ 56.872480][ T5077] [ 56.882953][ T5077] [ 56.882953][ T5077] the existing dependency chain (in reverse order) is: [ 56.891961][ T5077] [ 56.891961][ T5077] -> #2 (clock-AF_INET){++..}-{2:2}: [ 56.899442][ T5077] _raw_read_lock_bh+0x3f/0x70 [ 56.904750][ T5077] sock_i_uid+0x1f/0xb0 [ 56.909449][ T5077] inet_csk_get_port+0x85f/0x26d0 [ 56.915018][ T5077] inet_csk_listen_start+0x1ad/0x440 [ 56.920836][ T5077] inet_listen+0x235/0x640 [ 56.925777][ T5077] __sys_listen+0x181/0x250 [ 56.930811][ T5077] __x64_sys_listen+0x54/0x80 [ 56.936018][ T5077] do_syscall_64+0x39/0xb0 [ 56.940964][ T5077] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 56.947485][ T5077] [ 56.947485][ T5077] -> #1 (&tcp_hashinfo.bhash[i].lock){+.-.}-{2:2}: [ 56.956179][ T5077] _raw_spin_lock+0x2e/0x40 [ 56.961207][ T5077] __inet_inherit_port+0x2b5/0x18c0 [ 56.966950][ T5077] tcp_v4_syn_recv_sock+0xb5a/0x14b0 [ 56.972797][ T5077] tcp_check_req+0x632/0x1aa0 [ 56.978032][ T5077] tcp_v4_rcv+0x2120/0x3280 [ 56.983072][ T5077] ip_protocol_deliver_rcu+0x9f/0x480 [ 56.988984][ T5077] ip_local_deliver_finish+0x2ec/0x4f0 [ 56.994981][ T5077] ip_local_deliver+0x1ae/0x200 [ 57.000377][ T5077] ip_sublist_rcv_finish+0x9a/0x2c0 [ 57.006457][ T5077] ip_list_rcv_finish.constprop.0+0x4f9/0x6c0 [ 57.013064][ T5077] ip_list_rcv+0x347/0x4a0 [ 57.018016][ T5077] __netif_receive_skb_list_core+0x548/0x8f0 [ 57.024522][ T5077] netif_receive_skb_list_internal+0x75f/0xdc0 [ 57.031203][ T5077] napi_complete_done+0x243/0x960 [ 57.036755][ T5077] virtnet_poll+0xd08/0x1300 [ 57.041873][ T5077] __napi_poll+0xaf/0x430 [ 57.046729][ T5077] net_rx_action+0x8da/0xc70 [ 57.051845][ T5077] __do_softirq+0x2e3/0xae3 [ 57.056877][ T5077] __irq_exit_rcu+0x114/0x190 [ 57.062075][ T5077] irq_exit_rcu+0x9/0x20 [ 57.066840][ T5077] common_interrupt+0xad/0xd0 [ 57.072047][ T5077] asm_common_interrupt+0x26/0x40 [ 57.077593][ T5077] acpi_safe_halt+0x40/0x50 [ 57.082615][ T5077] acpi_idle_do_entry+0x53/0x70 [ 57.087991][ T5077] acpi_idle_enter+0x173/0x290 [ 57.093279][ T5077] cpuidle_enter_state+0xd3/0x6f0 [ 57.098823][ T5077] cpuidle_enter+0x4e/0xa0 [ 57.103773][ T5077] do_idle+0x348/0x440 [ 57.108375][ T5077] cpu_startup_entry+0x18/0x20 [ 57.113663][ T5077] rest_init+0x16d/0x2b0 [ 57.118427][ T5077] arch_call_rest_init+0x13/0x1c [ 57.123888][ T5077] start_kernel+0x44f/0x470 [ 57.128916][ T5077] secondary_startup_64_no_verify+0xce/0xdb [ 57.135340][ T5077] [ 57.135340][ T5077] -> #0 (slock-AF_INET){+.-.}-{2:2}: [ 57.142817][ T5077] __lock_acquire+0x2a9d/0x5780 [ 57.148189][ T5077] lock_acquire.part.0+0x11c/0x350 [ 57.153831][ T5077] _raw_spin_lock_bh+0x33/0x40 [ 57.159122][ T5077] release_sock+0x1f/0x1b0 [ 57.164060][ T5077] l2tp_tunnel_register+0x2e0/0xd80 [ 57.169791][ T5077] l2tp_nl_cmd_tunnel_create+0x3d6/0x8b0 [ 57.175956][ T5077] genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 [ 57.182645][ T5077] genl_rcv_msg+0x4ff/0x7e0 [ 57.187677][ T5077] netlink_rcv_skb+0x165/0x440 [ 57.192970][ T5077] genl_rcv+0x28/0x40 [ 57.197482][ T5077] netlink_unicast+0x547/0x7f0 [ 57.202775][ T5077] netlink_sendmsg+0x925/0xe20 [ 57.208073][ T5077] sock_sendmsg+0xde/0x190 [ 57.213020][ T5077] ____sys_sendmsg+0x71c/0x900 [ 57.218315][ T5077] ___sys_sendmsg+0x110/0x1b0 [ 57.223522][ T5077] __sys_sendmsg+0xf7/0x1c0 [ 57.228553][ T5077] do_syscall_64+0x39/0xb0 [ 57.233497][ T5077] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 57.239927][ T5077] [ 57.239927][ T5077] other info that might help us debug this: [ 57.239927][ T5077] [ 57.250144][ T5077] Chain exists of: [ 57.250144][ T5077] slock-AF_INET --> &tcp_hashinfo.bhash[i].lock --> clock-AF_INET [ 57.250144][ T5077] [ 57.263879][ T5077] Possible unsafe locking scenario: [ 57.263879][ T5077] [ 57.271315][ T5077] CPU0 CPU1 [ 57.276670][ T5077] ---- ---- [ 57.282028][ T5077] lock(clock-AF_INET); [ 57.286268][ T5077] lock(&tcp_hashinfo.bhash[i].lock); [ 57.294243][ T5077] lock(clock-AF_INET); [ 57.301005][ T5077] lock(slock-AF_INET); [ 57.305246][ T5077] [ 57.305246][ T5077] *** DEADLOCK *** [ 57.305246][ T5077] [ 57.313383][ T5077] 4 locks held by syz-executor383/5077: [ 57.318922][ T5077] #0: ffffffff8e15df10 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 [ 57.327125][ T5077] #1: ffffffff8e15dfc8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x51a/0x7e0 [ 57.336111][ T5077] #2: ffff888017e10fb0 (sk_lock-AF_INET){+.+.}-{0:0}, at: l2tp_tunnel_register+0x1af/0xd80 [ 57.346224][ T5077] #3: ffff888017e11238 (clock-AF_INET){++..}-{2:2}, at: l2tp_tunnel_register+0x1c3/0xd80 [ 57.356162][ T5077] [ 57.356162][ T5077] stack backtrace: [ 57.362039][ T5077] CPU: 1 PID: 5077 Comm: syz-executor383 Not tainted 6.2.0-rc4-next-20230117-syzkaller #0 [ 57.371928][ T5077] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 [ 57.381981][ T5077] Call Trace: [ 57.385257][ T5077] [ 57.388186][ T5077] dump_stack_lvl+0xd1/0x138 [ 57.392790][ T5077] check_noncircular+0x25f/0x2e0 [ 57.397733][ T5077] ? print_circular_bug+0x1e0/0x1e0 [ 57.402935][ T5077] ? register_lock_class+0xbe/0x1120 [ 57.408231][ T5077] __lock_acquire+0x2a9d/0x5780 [ 57.413093][ T5077] ? lockdep_hardirqs_on_prepare+0x410/0x410 [ 57.419083][ T5077] lock_acquire.part.0+0x11c/0x350 [ 57.424200][ T5077] ? release_sock+0x1f/0x1b0 [ 57.428795][ T5077] ? lock_sync+0x190/0x190 [ 57.433217][ T5077] ? release_sock+0x1f/0x1b0 [ 57.437811][ T5077] ? rcu_read_lock_sched_held+0x3e/0x70 [ 57.443361][ T5077] ? trace_lock_acquire+0x1f1/0x290 [ 57.448566][ T5077] ? l2tp_tunnel_register+0x1c3/0xd80 [ 57.453950][ T5077] ? rcu_read_lock_sched_held+0x3e/0x70 [ 57.459503][ T5077] ? release_sock+0x1f/0x1b0 [ 57.464097][ T5077] ? lock_acquire+0x32/0xc0 [ 57.468604][ T5077] ? release_sock+0x1f/0x1b0 [ 57.473208][ T5077] _raw_spin_lock_bh+0x33/0x40 [ 57.478067][ T5077] ? release_sock+0x1f/0x1b0 [ 57.482663][ T5077] release_sock+0x1f/0x1b0 [ 57.487086][ T5077] l2tp_tunnel_register+0x2e0/0xd80 [ 57.492298][ T5077] ? l2tp_exit_net+0x390/0x390 [ 57.497072][ T5077] ? debug_object_free+0x360/0x360 [ 57.502199][ T5077] ? lockdep_init_map_type+0x21e/0x800 [ 57.507664][ T5077] ? lockdep_init_map_type+0x21e/0x800 [ 57.513130][ T5077] ? l2tp_tunnel_create+0x2bf/0x4b0 [ 57.518337][ T5077] ? l2tp_tunnel_create+0x3c6/0x4b0 [ 57.523546][ T5077] l2tp_nl_cmd_tunnel_create+0x3d6/0x8b0 [ 57.529195][ T5077] ? l2tp_tunnel_notify.constprop.0+0x160/0x160 [ 57.535455][ T5077] ? genl_family_rcv_msg_attrs_parse.constprop.0+0x1b7/0x290 [ 57.542844][ T5077] ? genl_family_rcv_msg_attrs_parse.constprop.0+0xaf/0x290 [ 57.550148][ T5077] genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 [ 57.556317][ T5077] ? genl_start+0x660/0x660 [ 57.560835][ T5077] ? apparmor_capable+0x1dc/0x460 [ 57.565881][ T5077] ? ns_capable+0xe2/0x100 [ 57.570315][ T5077] genl_rcv_msg+0x4ff/0x7e0 [ 57.574832][ T5077] ? genl_family_rcv_msg_doit.isra.0+0x2d0/0x2d0 [ 57.581174][ T5077] ? l2tp_tunnel_notify.constprop.0+0x160/0x160 [ 57.587457][ T5077] ? lockdep_hardirqs_on_prepare+0x410/0x410 [ 57.593445][ T5077] ? kasan_save_stack+0x35/0x40 [ 57.598303][ T5077] ? kasan_save_stack+0x22/0x40 [ 57.603161][ T5077] ? kasan_set_track+0x25/0x30 [ 57.608282][ T5077] netlink_rcv_skb+0x165/0x440 [ 57.613060][ T5077] ? genl_family_rcv_msg_doit.isra.0+0x2d0/0x2d0 [ 57.619401][ T5077] ? netlink_ack+0x1370/0x1370 [ 57.624174][ T5077] ? trace_lock_acquire+0x1f1/0x290 [ 57.629389][ T5077] ? rwsem_down_read_slowpath+0xb20/0xb20 [ 57.635129][ T5077] ? netlink_deliver_tap+0x1b1/0xcf0 [ 57.640427][ T5077] genl_rcv+0x28/0x40 [ 57.644422][ T5077] netlink_unicast+0x547/0x7f0 [ 57.649200][ T5077] ? netlink_attachskb+0x890/0x890 [ 57.654321][ T5077] ? __virt_addr_valid+0x61/0x2e0 [ 57.659362][ T5077] ? __phys_addr_symbol+0x30/0x70 [ 57.664408][ T5077] ? __check_object_size+0x2e2/0x5a0 [ 57.669711][ T5077] netlink_sendmsg+0x925/0xe20 [ 57.674500][ T5077] ? netlink_unicast+0x7f0/0x7f0 [ 57.679451][ T5077] ? bpf_lsm_socket_sendmsg+0x9/0x10 [ 57.684751][ T5077] ? netlink_unicast+0x7f0/0x7f0 [ 57.689703][ T5077] sock_sendmsg+0xde/0x190 [ 57.694132][ T5077] ____sys_sendmsg+0x71c/0x900 [ 57.698906][ T5077] ? copy_msghdr_from_user+0xfc/0x150 [ 57.704291][ T5077] ? kernel_sendmsg+0x50/0x50 [ 57.708978][ T5077] ? __switch_to+0x5d0/0x1110 [ 57.713663][ T5077] ? lockdep_hardirqs_on_prepare+0x410/0x410 [ 57.719657][ T5077] ___sys_sendmsg+0x110/0x1b0 [ 57.724347][ T5077] ? do_recvmmsg+0x6e0/0x6e0 [ 57.728954][ T5077] ? lock_sync+0x190/0x190 [ 57.733376][ T5077] ? ptrace_stop.part.0+0x4e3/0x8e0 [ 57.738596][ T5077] ? rcu_read_lock_sched_held+0x3e/0x70 [ 57.744174][ T5077] ? do_raw_spin_lock+0x124/0x2b0 [ 57.749220][ T5077] ? rwlock_bug.part.0+0x90/0x90 [ 57.754176][ T5077] ? lock_acquire+0x32/0xc0 [ 57.758699][ T5077] ? ptrace_stop.part.0+0x4e3/0x8e0 [ 57.763920][ T5077] ? __fget_light+0x20a/0x270 [ 57.768627][ T5077] __sys_sendmsg+0xf7/0x1c0 [ 57.773156][ T5077] ? __sys_sendmsg_sock+0x40/0x40 [ 57.778205][ T5077] ? lockdep_hardirqs_on+0x7d/0x100 [ 57.783421][ T5077] ? _raw_spin_unlock_irq+0x2e/0x50 [ 57.788626][ T5077] ? ptrace_notify+0xfe/0x140 [ 57.793398][ T5077] do_syscall_64+0x39/0xb0 [ 57.797831][ T5077] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 57.803747][ T5077] RIP: 0033:0x7fcd4cb24bc9 [ 57.808598][ T5077] Code: 28 c3 e8 5a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 [ 57.828384][ T5077] RSP: 002b:00007fff6f2e5518 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 57.836810][ T5077] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcd4cb24bc9 [ 57.844785][ T5077] RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003 [ 57.852760][ T5077] RBP: 00007fcd4cae8590 R08: 0000000000000006 R09: 0000000000000000 sendmsg(3, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\x3c\x00\x00\x00\x30\x00\x23\x09\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x05\x00\x07\x00\x00\x00\x00\x00\x08\x00\x09\x00\x00\x00\x00\x00\x06\x00\x02\x00\x01\x00\x00\x00\x08\x00\x0a\x00\x00\x00\x00\x00\x08\x00\x17\x00\x04\x00\x00\x00", iov_len=60}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 60 exit_group(0) = ? +++ exited with 0 +++ [ 57.860735][ T5077] R10: 0000000000000009 R11: 0000