============================================ WARNING: possible recursive locking detected 5.11.0-syzkaller #0 Not tainted -------------------------------------------- syz-executor.0/5887 is trying to acquire lock: ffff888010b41398 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] ffff888010b41398 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4214 [inline] ffff888010b41398 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1ad/0x10c0 net/sched/sch_generic.c:311 but task is already holding lock: ffff88801aebb898 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] ffff88801aebb898 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4214 [inline] ffff88801aebb898 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1ad/0x10c0 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 9 locks held by syz-executor.0/5887: #0: ffffffff8a7684e0 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #0: ffffffff8a7684e0 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x220/0x1d50 net/ipv4/ip_output.c:216 #1: ffffffff8a7684e0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1be/0x2670 net/core/dev.c:4085 #2: ffff888014739258 (&sch->seqlock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:364 [inline] #2: ffff888014739258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:162 [inline] #2: ffff888014739258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run include/net/pkt_sched.h:130 [inline] #2: ffff888014739258 (&sch->seqlock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3765 [inline] #2: ffff888014739258 (&sch->seqlock){+...}-{2:2}, at: __dev_queue_xmit+0xf74/0x2670 net/core/dev.c:4119 #3: ffff888014739148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_output include/net/neighbour.h:510 [inline] #3: ffff888014739148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: ip_finish_output2+0x66f/0x1d50 net/ipv4/ip_output.c:230 #4: ffff88801aebb898 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] #4: ffff88801aebb898 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4214 [inline] #4: ffff88801aebb898 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1ad/0x10c0 net/sched/sch_generic.c:311 #5: ffffffff8a7684e0 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #5: ffffffff8a7684e0 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x220/0x1d50 net/ipv4/ip_output.c:216 #6: ffffffff8a7684e0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1be/0x2670 net/core/dev.c:4085 #7: ffff8880242fb258 (&sch->seqlock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:364 [inline] #7: ffff8880242fb258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:162 [inline] #7: ffff8880242fb258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run include/net/pkt_sched.h:130 [inline] #7: ffff8880242fb258 (&sch->seqlock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3765 [inline] #7: ffff8880242fb258 (&sch->seqlock){+...}-{2:2}, at: __dev_queue_xmit+0xf74/0x2670 net/core/dev.c:4119 #8: ffff8880242fb148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_output include/net/neighbour.h:510 [inline] #8: ffff8880242fb148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: ip_finish_output2+0x66f/0x1d50 net/ipv4/ip_output.c:230 stack backtrace: CPU: 1 PID: 5887 Comm: syz-executor.0 Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x9a/0xcc lib/dump_stack.c:120 print_deadlock_bug kernel/locking/lockdep.c:2761 [inline] check_deadlock kernel/locking/lockdep.c:2804 [inline] validate_chain kernel/locking/lockdep.c:3595 [inline] __lock_acquire.cold+0x117/0x3ab kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5442 [inline] lock_acquire+0x1a8/0x720 kernel/locking/lockdep.c:5407 __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:4214 [inline] sch_direct_xmit+0x1ad/0x10c0 net/sched/sch_generic.c:311 qdisc_restart net/sched/sch_generic.c:376 [inline] __qdisc_run+0x3d9/0x1470 net/sched/sch_generic.c:384 qdisc_run include/net/pkt_sched.h:136 [inline] qdisc_run include/net/pkt_sched.h:128 [inline] __dev_xmit_skb net/core/dev.c:3765 [inline] __dev_queue_xmit+0x1073/0x2670 net/core/dev.c:4119 neigh_output include/net/neighbour.h:510 [inline] ip_finish_output2+0x66f/0x1d50 net/ipv4/ip_output.c:230 iptunnel_xmit+0x533/0x970 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x13c6/0x23a0 net/ipv4/ip_tunnel.c:805 erspan_xmit+0xe13/0x2610 net/ipv4/ip_gre.c:702 __netdev_start_xmit include/linux/netdevice.h:4778 [inline] netdev_start_xmit include/linux/netdevice.h:4792 [inline] xmit_one net/core/dev.c:3574 [inline] dev_hard_start_xmit+0x1a5/0x6f0 net/core/dev.c:3590 sch_direct_xmit+0x223/0x10c0 net/sched/sch_generic.c:313 qdisc_restart net/sched/sch_generic.c:376 [inline] __qdisc_run+0x3d9/0x1470 net/sched/sch_generic.c:384 qdisc_run include/net/pkt_sched.h:136 [inline] qdisc_run include/net/pkt_sched.h:128 [inline] __dev_xmit_skb net/core/dev.c:3765 [inline] __dev_queue_xmit+0x1073/0x2670 net/core/dev.c:4119 neigh_output include/net/neighbour.h:510 [inline] ip_finish_output2+0x66f/0x1d50 net/ipv4/ip_output.c:230 dst_output include/net/dst.h:441 [inline] ip_local_out net/ipv4/ip_output.c:126 [inline] ip_send_skb+0x9f/0x1c0 net/ipv4/ip_output.c:1568 udp_send_skb+0x5d8/0x14d0 net/ipv4/udp.c:947 udp_sendmsg+0x173e/0x1fe0 net/ipv4/udp.c:1234 udpv6_sendmsg+0x5c6/0x2920 net/ipv6/udp.c:1351 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xab/0xe0 net/socket.c:672 ____sys_sendmsg+0x392/0x7a0 net/socket.c:2345 ___sys_sendmsg+0xd3/0x150 net/socket.c:2399 __sys_sendmmsg+0x141/0x300 net/socket.c:2489 __do_sys_sendmmsg net/socket.c:2518 [inline] __se_sys_sendmmsg net/socket.c:2515 [inline] __x64_sys_sendmmsg+0x94/0x100 net/socket.c:2515 do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f79b93c5109 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f79b8b3a168 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f79b94d7f60 RCX: 00007f79b93c5109 RDX: 0000000000000001 RSI: 0000000020004d80 RDI: 0000000000000004 RBP: 00007f79b941f05d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000004000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff7857447f R14: 00007f79b8b3a300 R15: 0000000000022000