============================================ WARNING: possible recursive locking detected 5.16.0-rc3-syzkaller #0 Not tainted -------------------------------------------- syz-executor.2/20671 is trying to acquire lock: ffff88804d620398 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] ffff88804d620398 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4125 [inline] ffff88804d620398 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x318/0xbe0 net/sched/sch_generic.c:340 but task is already holding lock: ffff88801a9f3898 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] ffff88801a9f3898 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4125 [inline] ffff88801a9f3898 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x318/0xbe0 net/sched/sch_generic.c:340 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 12 locks held by syz-executor.2/20671: #0: ffffffff8bb83b60 (rcu_read_lock){....}-{1:2}, at: l3mdev_l3_out include/net/l3mdev.h:198 [inline] #0: ffffffff8bb83b60 (rcu_read_lock){....}-{1:2}, at: l3mdev_ip6_out include/net/l3mdev.h:219 [inline] #0: ffffffff8bb83b60 (rcu_read_lock){....}-{1:2}, at: rawv6_send_hdrinc net/ipv6/raw.c:677 [inline] #0: ffffffff8bb83b60 (rcu_read_lock){....}-{1:2}, at: rawv6_sendmsg+0x1f3c/0x3a10 net/ipv6/raw.c:944 #1: ffffffff8bb83b00 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline] #1: ffffffff8bb83b00 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x2ad/0x14f0 net/ipv6/ip6_output.c:112 #2: ffffffff8bb83b00 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1e3/0x3640 net/core/dev.c:4036 #3: ffff88804fc6d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:359 [inline] #3: ffff88804fc6d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:187 [inline] #3: ffff88804fc6d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:184 [inline] #3: ffff88804fc6d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3687 [inline] #3: ffff88804fc6d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x1262/0x3640 net/core/dev.c:4077 #4: ffff88801a9f3898 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #4: ffff88801a9f3898 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4125 [inline] #4: ffff88801a9f3898 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x318/0xbe0 net/sched/sch_generic.c:340 #5: ffff88814a5f5070 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:359 [inline] #5: ffff88814a5f5070 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock net/ipv6/icmp.c:117 [inline] #5: ffff88814a5f5070 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmp6_send+0xe22/0x2650 net/ipv6/icmp.c:547 #6: ffffffff8bb83b60 (rcu_read_lock){....}-{1:2}, at: icmp6_send+0x13f7/0x2650 net/ipv6/icmp.c:607 #7: ffffffff8bb83b00 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline] #7: ffffffff8bb83b00 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x2ad/0x14f0 net/ipv6/ip6_output.c:112 #8: ffffffff8bb83b60 (rcu_read_lock){....}-{1:2}, at: ip6_nd_hdr net/ipv6/ndisc.c:466 [inline] #8: ffffffff8bb83b60 (rcu_read_lock){....}-{1:2}, at: ndisc_send_skb+0x84b/0x17f0 net/ipv6/ndisc.c:502 #9: ffffffff8bb83b00 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline] #9: ffffffff8bb83b00 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x2ad/0x14f0 net/ipv6/ip6_output.c:112 #10: ffffffff8bb83b00 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1e3/0x3640 net/core/dev.c:4036 #11: ffff888018ca5258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:359 [inline] #11: ffff888018ca5258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:187 [inline] #11: ffff888018ca5258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:184 [inline] #11: ffff888018ca5258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3687 [inline] #11: ffff888018ca5258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x1262/0x3640 net/core/dev.c:4077 stack backtrace: CPU: 0 PID: 20671 Comm: syz-executor.2 Not tainted 5.16.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2956 [inline] check_deadlock kernel/locking/lockdep.c:2999 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5637 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:349 [inline] __netif_tx_lock include/linux/netdevice.h:4125 [inline] sch_direct_xmit+0x318/0xbe0 net/sched/sch_generic.c:340 __dev_xmit_skb net/core/dev.c:3700 [inline] __dev_queue_xmit+0x148f/0x3640 net/core/dev.c:4077 neigh_resolve_output net/core/neighbour.c:1523 [inline] neigh_resolve_output+0x50e/0x820 net/core/neighbour.c:1503 neigh_output include/net/neighbour.h:541 [inline] ip6_finish_output2+0x56e/0x14f0 net/ipv6/ip6_output.c:126 __ip6_finish_output net/ipv6/ip6_output.c:191 [inline] __ip6_finish_output+0x61e/0xe80 net/ipv6/ip6_output.c:170 ip6_finish_output+0x32/0x200 net/ipv6/ip6_output.c:201 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:224 dst_output include/net/dst.h:451 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] ndisc_send_skb+0xa99/0x17f0 net/ipv6/ndisc.c:508 ndisc_send_ns+0x3a9/0x840 net/ipv6/ndisc.c:650 ndisc_solicit+0x2cd/0x4f0 net/ipv6/ndisc.c:742 neigh_probe+0xc2/0x110 net/core/neighbour.c:1041 __neigh_event_send+0x37d/0x1570 net/core/neighbour.c:1202 neigh_event_send include/net/neighbour.h:470 [inline] neigh_resolve_output+0x538/0x820 net/core/neighbour.c:1507 neigh_output include/net/neighbour.h:541 [inline] ip6_finish_output2+0x56e/0x14f0 net/ipv6/ip6_output.c:126 __ip6_finish_output net/ipv6/ip6_output.c:191 [inline] __ip6_finish_output+0x61e/0xe80 net/ipv6/ip6_output.c:170 ip6_finish_output+0x32/0x200 net/ipv6/ip6_output.c:201 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:224 dst_output include/net/dst.h:451 [inline] ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:161 ip6_send_skb+0xb7/0x340 net/ipv6/ip6_output.c:1912 ip6_push_pending_frames+0xdd/0x100 net/ipv6/ip6_output.c:1932 icmpv6_push_pending_frames+0x294/0x470 net/ipv6/icmp.c:310 icmp6_send+0x1dad/0x2650 net/ipv6/icmp.c:626 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x2d/0x520 net/ipv6/route.c:2790 dst_link_failure include/net/dst.h:430 [inline] ip_tunnel_xmit+0x160c/0x2b60 net/ipv4/ip_tunnel.c:816 erspan_xmit+0x7e2/0x29c0 net/ipv4/ip_gre.c:712 __netdev_start_xmit include/linux/netdevice.h:4685 [inline] netdev_start_xmit include/linux/netdevice.h:4699 [inline] xmit_one net/core/dev.c:3473 [inline] dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3489 sch_direct_xmit+0x19f/0xbe0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3700 [inline] __dev_queue_xmit+0x148f/0x3640 net/core/dev.c:4077 neigh_resolve_output net/core/neighbour.c:1523 [inline] neigh_resolve_output+0x50e/0x820 net/core/neighbour.c:1503 neigh_output include/net/neighbour.h:541 [inline] ip6_finish_output2+0x56e/0x14f0 net/ipv6/ip6_output.c:126 __ip6_finish_output net/ipv6/ip6_output.c:191 [inline] __ip6_finish_output+0x61e/0xe80 net/ipv6/ip6_output.c:170 ip6_finish_output+0x32/0x200 net/ipv6/ip6_output.c:201 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:224 dst_output include/net/dst.h:451 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] rawv6_send_hdrinc net/ipv6/raw.c:687 [inline] rawv6_sendmsg+0x216a/0x3a10 net/ipv6/raw.c:944 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:817 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 ____sys_sendmsg+0x331/0x810 net/socket.c:2409 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463 __sys_sendmmsg+0x195/0x470 net/socket.c:2549 __do_sys_sendmmsg net/socket.c:2578 [inline] __se_sys_sendmmsg net/socket.c:2575 [inline] __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2575 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f93513c6af9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f935033c188 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f93514d9f60 RCX: 00007f93513c6af9 RDX: 0000000000000001 RSI: 0000000020000380 RDI: 0000000000000003 RBP: 00007f9351420ff7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcd17d8c0f R14: 00007f935033c300 R15: 0000000000022000