====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc5-syzkaller-00171-gb2ff42c6d3ab #0 Not tainted ------------------------------------------------------ syz-executor.4/18511 is trying to acquire lock: ffff88807db3d4d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88807db3d4d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4371 [inline] ffff88807db3d4d8 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}, at: sch_direct_xmit+0x1c4/0x5f0 net/sched/sch_generic.c:341 but task is already holding lock: ffff88801e3488d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88801e3488d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4371 [inline] ffff88801e3488d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x179d/0x3ca0 net/core/dev.c:4337 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __netif_tx_lock include/linux/netdevice.h:4371 [inline] __dev_queue_xmit+0x179d/0x3ca0 net/core/dev.c:4337 neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0xe70/0x1380 net/ipv4/ip_output.c:235 iptunnel_xmit+0x540/0x9b0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x20ef/0x2940 net/ipv4/ip_tunnel.c:857 erspan_xmit+0xa18/0x1500 net/ipv4/ip_gre.c:725 __netdev_start_xmit include/linux/netdevice.h:4903 [inline] netdev_start_xmit include/linux/netdevice.h:4917 [inline] xmit_one net/core/dev.c:3531 [inline] dev_hard_start_xmit+0x27a/0x7e0 net/core/dev.c:3547 sch_direct_xmit+0x2b6/0x5f0 net/sched/sch_generic.c:343 __dev_xmit_skb net/core/dev.c:3760 [inline] __dev_queue_xmit+0x19eb/0x3ca0 net/core/dev.c:4307 neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0xe70/0x1380 net/ipv4/ip_output.c:235 ip_local_out net/ipv4/ip_output.c:129 [inline] ip_send_skb+0x74/0x100 net/ipv4/ip_output.c:1492 udp_send_skb+0xaa4/0x1470 net/ipv4/udp.c:968 udp_sendmsg+0x1c21/0x2a60 net/ipv4/udp.c:1256 udpv6_sendmsg+0x1383/0x3270 net/ipv6/udp.c:1388 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0xef/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmmsg+0x3b2/0x740 net/socket.c:2724 __do_sys_sendmmsg net/socket.c:2753 [inline] __se_sys_sendmmsg net/socket.c:2750 [inline] __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2750 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&qdisc_xmit_lock_key#3){+.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __netif_tx_lock include/linux/netdevice.h:4371 [inline] sch_direct_xmit+0x1c4/0x5f0 net/sched/sch_generic.c:341 __dev_xmit_skb net/core/dev.c:3760 [inline] __dev_queue_xmit+0x19eb/0x3ca0 net/core/dev.c:4307 dev_queue_xmit include/linux/netdevice.h:3091 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip6_finish_output2+0xfc0/0x1670 net/ipv6/ip6_output.c:137 ip6_finish_output+0x41e/0x810 net/ipv6/ip6_output.c:222 NF_HOOK include/linux/netfilter.h:314 [inline] ndisc_send_skb+0xab0/0x1380 net/ipv6/ndisc.c:509 ndisc_solicit+0x493/0x6a0 neigh_probe net/core/neighbour.c:1075 [inline] __neigh_event_send+0xec8/0x15a0 net/core/neighbour.c:1242 neigh_event_send_probe include/net/neighbour.h:466 [inline] neigh_event_send include/net/neighbour.h:472 [inline] neigh_resolve_output+0x1b5/0x740 net/core/neighbour.c:1547 neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0xff8/0x1670 net/ipv6/ip6_output.c:137 ip6_finish_output+0x41e/0x810 net/ipv6/ip6_output.c:222 ip6_send_skb+0x112/0x230 net/ipv6/ip6_output.c:1955 icmp6_send+0x15fc/0x2070 net/ipv6/icmp.c:624 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x3c/0x4f0 net/ipv6/route.c:2797 dst_link_failure include/net/dst.h:429 [inline] vti6_xmit net/ipv6/ip6_vti.c:547 [inline] vti6_tnl_xmit+0x13be/0x1bd0 net/ipv6/ip6_vti.c:585 __netdev_start_xmit include/linux/netdevice.h:4903 [inline] netdev_start_xmit include/linux/netdevice.h:4917 [inline] xmit_one net/core/dev.c:3531 [inline] dev_hard_start_xmit+0x27a/0x7e0 net/core/dev.c:3547 __dev_queue_xmit+0x1ad1/0x3ca0 net/core/dev.c:4341 packet_snd net/packet/af_packet.c:3081 [inline] packet_sendmsg+0x46a9/0x6130 net/packet/af_packet.c:3113 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 __sys_sendto+0x3a4/0x4f0 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2199 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&qdisc_xmit_lock_key#2); lock(&qdisc_xmit_lock_key#3); lock(&qdisc_xmit_lock_key#2); lock(&qdisc_xmit_lock_key#3); *** DEADLOCK *** 9 locks held by syz-executor.4/18511: #0: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #0: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:833 [inline] #0: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c7/0x3ca0 net/core/dev.c:4266 #1: ffff88801e3488d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #1: ffff88801e3488d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4371 [inline] #1: ffff88801e3488d8 (&qdisc_xmit_lock_key#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x179d/0x3ca0 net/core/dev.c:4337 #2: ffff88802a6a01d8 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #2: ffff88802a6a01d8 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock net/ipv6/icmp.c:108 [inline] #2: ffff88802a6a01d8 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmp6_send+0xc45/0x2070 net/ipv6/icmp.c:545 #3: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #3: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: icmp6_send+0xba4/0x2070 net/ipv6/icmp.c:537 #4: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #4: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #4: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x712/0x1670 net/ipv6/ip6_output.c:122 #5: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #5: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #5: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: ip6_nd_hdr net/ipv6/ndisc.c:452 [inline] #5: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: ndisc_send_skb+0x572/0x1380 net/ipv6/ndisc.c:503 #6: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #6: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #6: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x712/0x1670 net/ipv6/ip6_output.c:122 #7: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #7: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:833 [inline] #7: ffffffff8e334d80 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c7/0x3ca0 net/core/dev.c:4266 #8: ffff88805e8fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #8: ffff88805e8fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:196 [inline] #8: ffff88805e8fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3747 [inline] #8: ffff88805e8fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_queue_xmit+0x1286/0x3ca0 net/core/dev.c:4307 stack backtrace: CPU: 0 PID: 18511 Comm: syz-executor.4 Not tainted 6.9.0-rc5-syzkaller-00171-gb2ff42c6d3ab #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __netif_tx_lock include/linux/netdevice.h:4371 [inline] sch_direct_xmit+0x1c4/0x5f0 net/sched/sch_generic.c:341 __dev_xmit_skb net/core/dev.c:3760 [inline] __dev_queue_xmit+0x19eb/0x3ca0 net/core/dev.c:4307 dev_queue_xmit include/linux/netdevice.h:3091 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip6_finish_output2+0xfc0/0x1670 net/ipv6/ip6_output.c:137 ip6_finish_output+0x41e/0x810 net/ipv6/ip6_output.c:222 NF_HOOK include/linux/netfilter.h:314 [inline] ndisc_send_skb+0xab0/0x1380 net/ipv6/ndisc.c:509 ndisc_solicit+0x493/0x6a0 neigh_probe net/core/neighbour.c:1075 [inline] __neigh_event_send+0xec8/0x15a0 net/core/neighbour.c:1242 neigh_event_send_probe include/net/neighbour.h:466 [inline] neigh_event_send include/net/neighbour.h:472 [inline] neigh_resolve_output+0x1b5/0x740 net/core/neighbour.c:1547 neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0xff8/0x1670 net/ipv6/ip6_output.c:137 ip6_finish_output+0x41e/0x810 net/ipv6/ip6_output.c:222 ip6_send_skb+0x112/0x230 net/ipv6/ip6_output.c:1955 icmp6_send+0x15fc/0x2070 net/ipv6/icmp.c:624 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x3c/0x4f0 net/ipv6/route.c:2797 dst_link_failure include/net/dst.h:429 [inline] vti6_xmit net/ipv6/ip6_vti.c:547 [inline] vti6_tnl_xmit+0x13be/0x1bd0 net/ipv6/ip6_vti.c:585 __netdev_start_xmit include/linux/netdevice.h:4903 [inline] netdev_start_xmit include/linux/netdevice.h:4917 [inline] xmit_one net/core/dev.c:3531 [inline] dev_hard_start_xmit+0x27a/0x7e0 net/core/dev.c:3547 __dev_queue_xmit+0x1ad1/0x3ca0 net/core/dev.c:4341 packet_snd net/packet/af_packet.c:3081 [inline] packet_sendmsg+0x46a9/0x6130 net/packet/af_packet.c:3113 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 __sys_sendto+0x3a4/0x4f0 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2199 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe13b87dea9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe13c51d0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007fe13b9abf80 RCX: 00007fe13b87dea9 RDX: 0000000000000028 RSI: 0000000020000100 RDI: 0000000000000005 RBP: 00007fe13b8ca4a4 R08: 0000000020000240 R09: 0000000000000014 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fe13b9abf80 R15: 00007ffc3445c7f8 netlink: 248 bytes leftover after parsing attributes in process `syz-executor.4'.