netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0 ============================================ WARNING: possible recursive locking detected 5.8.0-rc7-next-20200731-syzkaller #0 Not tainted -------------------------------------------- syz-executor302/6855 is trying to acquire lock: ffff8880a266a098 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] ffff8880a266a098 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4104 [inline] ffff8880a266a098 (_xmit_ETHER#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x215e/0x2d60 net/core/dev.c:4133 but task is already holding lock: ffff88809a154898 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] ffff88809a154898 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4104 [inline] ffff88809a154898 (_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-executor302/6855: #0: ffffffff89c52a80 (rcu_read_lock){....}-{1:2}, at: l3mdev_l3_out include/net/l3mdev.h:198 [inline] #0: ffffffff89c52a80 (rcu_read_lock){....}-{1:2}, at: l3mdev_ip6_out include/net/l3mdev.h:219 [inline] #0: ffffffff89c52a80 (rcu_read_lock){....}-{1:2}, at: rawv6_send_hdrinc net/ipv6/raw.c:677 [inline] #0: ffffffff89c52a80 (rcu_read_lock){....}-{1:2}, at: rawv6_sendmsg+0x1dda/0x38f0 net/ipv6/raw.c:944 #1: ffffffff89c52a20 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #1: ffffffff89c52a20 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x190/0x17b0 net/ipv6/ip6_output.c:103 #2: ffffffff89c52a20 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1da/0x2d60 net/core/dev.c:4072 #3: ffff88809ee0a258 (&sch->seqlock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:364 [inline] #3: ffff88809ee0a258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:159 [inline] #3: ffff88809ee0a258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run include/net/pkt_sched.h:128 [inline] #3: ffff88809ee0a258 (&sch->seqlock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3753 [inline] #3: ffff88809ee0a258 (&sch->seqlock){+...}-{2:2}, at: __dev_queue_xmit+0x1310/0x2d60 net/core/dev.c:4106 #4: ffff88809ee0a148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_resolve_output net/core/neighbour.c:1489 [inline] #4: ffff88809ee0a148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_resolve_output+0x3fe/0x6a0 net/core/neighbour.c:1469 #5: ffff88809a154898 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] #5: ffff88809a154898 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4104 [inline] #5: ffff88809a154898 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x256/0xbd0 net/sched/sch_generic.c:311 #6: ffff888098c70860 (k-slock-AF_INET6){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:364 [inline] #6: ffff888098c70860 (k-slock-AF_INET6){+...}-{2:2}, at: icmpv6_xmit_lock net/ipv6/icmp.c:117 [inline] #6: ffff888098c70860 (k-slock-AF_INET6){+...}-{2:2}, at: icmp6_send+0xe82/0x2670 net/ipv6/icmp.c:538 #7: ffffffff89c52a80 (rcu_read_lock){....}-{1:2}, at: icmp6_send+0x145d/0x2670 net/ipv6/icmp.c:598 #8: ffffffff89c52a20 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #8: ffffffff89c52a20 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x190/0x17b0 net/ipv6/ip6_output.c:103 #9: ffffffff89c52a20 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1da/0x2d60 net/core/dev.c:4072 stack backtrace: CPU: 0 PID: 6855 Comm: syz-executor302 Not tainted 5.8.0-rc7-next-20200731-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:4424 lock_acquire+0x1f1/0xad0 kernel/locking/lockdep.c:5003 __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:4104 [inline] __dev_queue_xmit+0x215e/0x2d60 net/core/dev.c:4133 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] 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:4630 [inline] netdev_start_xmit include/linux/netdevice.h:4644 [inline] xmit_one net/core/dev.c:3562 [inline] dev_hard_start_xmit+0x193/0x950 net/core/dev.c:3578 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:3753 [inline] __dev_queue_xmit+0x1456/0x2d60 net/core/dev.c:4106 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:1876 [inline] new_sync_write+0x422/0x650 fs/read_write.c:515 vfs_write+0x5ad/0x730 fs/read_write.c:595 ksys_write+0x1ee/0x250 fs/read_write.c:648 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x4491e9 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 2b 0e fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff06d83018 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fff06d83090 RCX: 00000000004491e9 RDX: 0000000000000028 RSI: 0000000020000140 RDI: 0000000000000005 RBP: 0000000000000000 R08: 00000000000000ff R09: 00000000000000ff R10: 00000000000000ff R11: 0000000000000246 R12: 0000000000000004 R13: 0000000000000003 R14: 000000000131d850 R15: 0000000000000001