============================================ WARNING: possible recursive locking detected 5.8.0-syzkaller #0 Not tainted -------------------------------------------- syz-executor529/7243 is trying to acquire lock: ffff88809789cc98 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] ffff88809789cc98 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4108 [inline] ffff88809789cc98 (_xmit_ETHER#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x215e/0x2d60 net/core/dev.c:4132 but task is already holding lock: ffff8880a72a0c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] ffff8880a72a0c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4108 [inline] ffff8880a72a0c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x256/0xbd0 net/sched/sch_generic.c:311 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(_xmit_ETHER#2); lock(_xmit_ETHER#2); *** DEADLOCK *** May be due to missing lock nesting notation 10 locks held by syz-executor529/7243: #0: ffffffff89bd62c0 (rcu_read_lock){....}-{1:2}, at: l3mdev_l3_out include/net/l3mdev.h:198 [inline] #0: ffffffff89bd62c0 (rcu_read_lock){....}-{1:2}, at: l3mdev_ip6_out include/net/l3mdev.h:219 [inline] #0: ffffffff89bd62c0 (rcu_read_lock){....}-{1:2}, at: rawv6_send_hdrinc net/ipv6/raw.c:677 [inline] #0: ffffffff89bd62c0 (rcu_read_lock){....}-{1:2}, at: rawv6_sendmsg+0x1dda/0x38f0 net/ipv6/raw.c:944 #1: ffffffff89bd6260 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #1: ffffffff89bd6260 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x190/0x17b0 net/ipv6/ip6_output.c:103 #2: ffffffff89bd6260 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1da/0x2d60 net/core/dev.c:4071 #3: ffff8880a2e8a258 (&sch->seqlock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:364 [inline] #3: ffff8880a2e8a258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:159 [inline] #3: ffff8880a2e8a258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run include/net/pkt_sched.h:128 [inline] #3: ffff8880a2e8a258 (&sch->seqlock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3752 [inline] #3: ffff8880a2e8a258 (&sch->seqlock){+...}-{2:2}, at: __dev_queue_xmit+0x1310/0x2d60 net/core/dev.c:4105 #4: ffff8880a2e8a148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_resolve_output net/core/neighbour.c:1489 [inline] #4: ffff8880a2e8a148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_resolve_output+0x3fe/0x6a0 net/core/neighbour.c:1469 #5: ffff8880a72a0c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] #5: ffff8880a72a0c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4108 [inline] #5: ffff8880a72a0c98 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x256/0xbd0 net/sched/sch_generic.c:311 #6: ffff88809ab29120 (k-slock-AF_INET6){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:364 [inline] #6: ffff88809ab29120 (k-slock-AF_INET6){+...}-{2:2}, at: icmpv6_xmit_lock net/ipv6/icmp.c:117 [inline] #6: ffff88809ab29120 (k-slock-AF_INET6){+...}-{2:2}, at: icmp6_send+0xe82/0x2670 net/ipv6/icmp.c:538 #7: ffffffff89bd62c0 (rcu_read_lock){....}-{1:2}, at: icmp6_send+0x145d/0x2670 net/ipv6/icmp.c:598 #8: ffffffff89bd6260 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #8: ffffffff89bd6260 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x190/0x17b0 net/ipv6/ip6_output.c:103 #9: ffffffff89bd6260 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1da/0x2d60 net/core/dev.c:4071 stack backtrace: CPU: 0 PID: 7243 Comm: syz-executor529 Not tainted 5.8.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 print_deadlock_bug kernel/locking/lockdep.c:2391 [inline] check_deadlock kernel/locking/lockdep.c:2432 [inline] validate_chain kernel/locking/lockdep.c:3202 [inline] __lock_acquire.cold+0x115/0x396 kernel/locking/lockdep.c:4426 lock_acquire+0x1f1/0xad0 kernel/locking/lockdep.c:5005 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] __netif_tx_lock include/linux/netdevice.h:4108 [inline] __dev_queue_xmit+0x215e/0x2d60 net/core/dev.c:4132 neigh_hh_output include/net/neighbour.h:498 [inline] neigh_output include/net/neighbour.h:507 [inline] ip6_finish_output2+0x7f1/0x17b0 net/ipv6/ip6_output.c:117 __ip6_finish_output net/ipv6/ip6_output.c:143 [inline] __ip6_finish_output+0x447/0xab0 net/ipv6/ip6_output.c:128 ip6_finish_output+0x34/0x1f0 net/ipv6/ip6_output.c:153 NF_HOOK_COND include/linux/netfilter.h:290 [inline] ip6_output+0x1db/0x520 net/ipv6/ip6_output.c:176 dst_output include/net/dst.h:443 [inline] ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:179 ip6_send_skb+0xb7/0x340 net/ipv6/ip6_output.c:1867 ip6_push_pending_frames+0xbd/0xe0 net/ipv6/ip6_output.c:1887 icmpv6_push_pending_frames+0x294/0x470 net/ipv6/icmp.c:304 icmp6_send+0x1cf6/0x2670 net/ipv6/icmp.c:617 icmpv6_send include/linux/icmpv6.h:24 [inline] ip6_link_failure+0x29/0x510 net/ipv6/route.c:2669 dst_link_failure include/net/dst.h:426 [inline] ip_tunnel_xmit+0x15cc/0x2ac3 net/ipv4/ip_tunnel.c:822 erspan_xmit+0x1109/0x2760 net/ipv4/ip_gre.c:704 __netdev_start_xmit include/linux/netdevice.h:4634 [inline] netdev_start_xmit include/linux/netdevice.h:4648 [inline] xmit_one net/core/dev.c:3561 [inline] dev_hard_start_xmit+0x193/0x950 net/core/dev.c:3577 sch_direct_xmit+0x2e1/0xbd0 net/sched/sch_generic.c:313 qdisc_restart net/sched/sch_generic.c:376 [inline] __qdisc_run+0x4b9/0x1620 net/sched/sch_generic.c:384 qdisc_run include/net/pkt_sched.h:134 [inline] qdisc_run include/net/pkt_sched.h:126 [inline] __dev_xmit_skb net/core/dev.c:3752 [inline] __dev_queue_xmit+0x1456/0x2d60 net/core/dev.c:4105 neigh_resolve_output net/core/neighbour.c:1489 [inline] neigh_resolve_output+0x3fe/0x6a0 net/core/neighbour.c:1469 neigh_output include/net/neighbour.h:509 [inline] ip6_finish_output2+0x8b6/0x17b0 net/ipv6/ip6_output.c:117 __ip6_finish_output net/ipv6/ip6_output.c:143 [inline] __ip6_finish_output+0x447/0xab0 net/ipv6/ip6_output.c:128 ip6_finish_output+0x34/0x1f0 net/ipv6/ip6_output.c:153 NF_HOOK_COND include/linux/netfilter.h:290 [inline] ip6_output+0x1db/0x520 net/ipv6/ip6_output.c:176 dst_output include/net/dst.h:443 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] rawv6_send_hdrinc net/ipv6/raw.c:687 [inline] rawv6_sendmsg+0x2008/0x38f0 net/ipv6/raw.c:944 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:817 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:671 sock_write_iter+0x28c/0x3c0 net/socket.c:998 call_write_iter include/linux/fs.h:1872 [inline] new_sync_write+0x422/0x650 fs/read_write.c:503 vfs_write+0x5ad/0x730 fs/read_write.c:578 ksys_write+0x1ee/0x250 fs/read_write.c:631 do_syscall_32_irqs_on arch/x86/entry/common.c:84 [inline] __do_fast_syscall_32+0x57/0x80 arch/x86/entry/common.c:126 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:149 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7fd1569 Code: 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000ffa19a2c EFLAGS: 00000217 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000020000140 RDX: 0000000000000028 RSI: 000000000000016a RDI: 0000000000000005 RBP: 00000000200004c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000