============================================ WARNING: possible recursive locking detected 5.7.0-rc2-syzkaller #0 Not tainted -------------------------------------------- syz-executor.0/3442 is trying to acquire lock: ffff888226e35398 (_xmit_ETHER){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:353 [inline] ffff888226e35398 (_xmit_ETHER){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4068 [inline] ffff888226e35398 (_xmit_ETHER){+.-.}-{2:2}, at: sch_direct_xmit+0x143/0x380 net/sched/sch_generic.c:311 but task is already holding lock: ffff88822e21d898 (_xmit_ETHER){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:353 [inline] ffff88822e21d898 (_xmit_ETHER){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4068 [inline] ffff88822e21d898 (_xmit_ETHER){+.-.}-{2:2}, at: sch_direct_xmit+0x143/0x380 net/sched/sch_generic.c:311 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(_xmit_ETHER); lock(_xmit_ETHER); *** DEADLOCK *** May be due to missing lock nesting notation 9 locks held by syz-executor.0/3442: #0: ffffffff836813a0 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #0: ffffffff836813a0 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x114/0x1030 net/ipv4/ip_output.c:214 #1: ffffffff836813a0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x81/0x1580 net/core/dev.c:4055 #2: ffff888226e33258 (&sch->seqlock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:363 [inline] #2: ffff888226e33258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:159 [inline] #2: ffff888226e33258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run include/net/pkt_sched.h:128 [inline] #2: ffff888226e33258 (&sch->seqlock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3736 [inline] #2: ffff888226e33258 (&sch->seqlock){+...}-{2:2}, at: __dev_queue_xmit+0x8b4/0x1580 net/core/dev.c:4089 #3: ffff888226e33148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_resolve_output net/core/neighbour.c:1489 [inline] #3: ffff888226e33148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_resolve_output+0x2ed/0x310 net/core/neighbour.c:1469 #4: ffff88822e21d898 (_xmit_ETHER){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:353 [inline] #4: ffff88822e21d898 (_xmit_ETHER){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4068 [inline] #4: ffff88822e21d898 (_xmit_ETHER){+.-.}-{2:2}, at: sch_direct_xmit+0x143/0x380 net/sched/sch_generic.c:311 #5: ffffffff836813a0 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #5: ffffffff836813a0 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x114/0x1030 net/ipv4/ip_output.c:214 #6: ffffffff836813a0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x81/0x1580 net/core/dev.c:4055 #7: ffff888226e68258 (&sch->seqlock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:363 [inline] #7: ffff888226e68258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:159 [inline] #7: ffff888226e68258 (&sch->seqlock){+...}-{2:2}, at: qdisc_run include/net/pkt_sched.h:128 [inline] #7: ffff888226e68258 (&sch->seqlock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3736 [inline] #7: ffff888226e68258 (&sch->seqlock){+...}-{2:2}, at: __dev_queue_xmit+0x8b4/0x1580 net/core/dev.c:4089 #8: ffff888226e68148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_resolve_output net/core/neighbour.c:1489 [inline] #8: ffff888226e68148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: neigh_resolve_output+0x2ed/0x310 net/core/neighbour.c:1469 stack backtrace: CPU: 1 PID: 3442 Comm: syz-executor.0 Not tainted 5.7.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xcd/0x12e lib/dump_stack.c:118 print_deadlock_bug kernel/locking/lockdep.c:2410 [inline] check_deadlock kernel/locking/lockdep.c:2451 [inline] validate_chain kernel/locking/lockdep.c:3221 [inline] __lock_acquire.cold.68+0x12d/0x2cc kernel/locking/lockdep.c:4355 lock_acquire+0x9e/0x300 kernel/locking/lockdep.c:4934 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x20/0x30 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:353 [inline] __netif_tx_lock include/linux/netdevice.h:4068 [inline] sch_direct_xmit+0x143/0x380 net/sched/sch_generic.c:311 qdisc_restart net/sched/sch_generic.c:376 [inline] __qdisc_run+0x215/0x890 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:3736 [inline] __dev_queue_xmit+0x951/0x1580 net/core/dev.c:4089 neigh_resolve_output net/core/neighbour.c:1489 [inline] neigh_resolve_output+0x2ed/0x310 net/core/neighbour.c:1469 neigh_output include/net/neighbour.h:510 [inline] ip_finish_output2+0x3e9/0x1030 net/ipv4/ip_output.c:228 __ip_finish_output net/ipv4/ip_output.c:306 [inline] __ip_finish_output+0x345/0x500 net/ipv4/ip_output.c:288 ip_finish_output net/ipv4/ip_output.c:316 [inline] NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0xb3/0x390 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:435 [inline] ip_local_out+0x6b/0xc0 net/ipv4/ip_output.c:125 iptunnel_xmit+0x1ee/0x2b0 net/ipv4/ip_tunnel_core.c:81 ip_tunnel_xmit+0x982/0x1610 net/ipv4/ip_tunnel.c:814 erspan_xmit+0x40e/0xee0 net/ipv4/ip_gre.c:683 __netdev_start_xmit include/linux/netdevice.h:4587 [inline] netdev_start_xmit include/linux/netdevice.h:4601 [inline] xmit_one net/core/dev.c:3545 [inline] dev_hard_start_xmit+0xd6/0x440 net/core/dev.c:3561 sch_direct_xmit+0x17c/0x380 net/sched/sch_generic.c:313 qdisc_restart net/sched/sch_generic.c:376 [inline] __qdisc_run+0x215/0x890 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:3736 [inline] __dev_queue_xmit+0x951/0x1580 net/core/dev.c:4089 neigh_resolve_output net/core/neighbour.c:1489 [inline] neigh_resolve_output+0x2ed/0x310 net/core/neighbour.c:1469 neigh_output include/net/neighbour.h:510 [inline] ip_finish_output2+0x3e9/0x1030 net/ipv4/ip_output.c:228 __ip_finish_output net/ipv4/ip_output.c:306 [inline] __ip_finish_output+0x345/0x500 net/ipv4/ip_output.c:288 ip_finish_output net/ipv4/ip_output.c:316 [inline] NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0xb3/0x390 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:435 [inline] ip_local_out+0x6b/0xc0 net/ipv4/ip_output.c:125 ip_send_skb+0x1c/0x80 net/ipv4/ip_output.c:1560 udp_send_skb.isra.51+0x226/0x5e0 net/ipv4/udp.c:891 udp_sendmsg+0x1082/0x1700 net/ipv4/udp.c:1178 udpv6_sendmsg+0xb17/0x1730 net/ipv6/udp.c:1286 inet6_sendmsg+0x4c/0x60 net/ipv6/af_inet6.c:577 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0x52/0x70 net/socket.c:672 ____sys_sendmsg+0x1a6/0x390 net/socket.c:2362 ___sys_sendmsg+0x95/0xd0 net/socket.c:2416 __sys_sendmmsg+0x104/0x330 net/socket.c:2506 __do_sys_sendmmsg net/socket.c:2535 [inline] __se_sys_sendmmsg net/socket.c:2532 [inline] __x64_sys_sendmmsg+0x24/0x30 net/socket.c:2532 do_syscall_64+0x91/0x300 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x7f6d1a2d78a9 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6d1a25d0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f6d1a3e9f60 RCX: 00007f6d1a2d78a9 RDX: 0000000000000001 RSI: 0000000020004d80 RDI: 0000000000000004 RBP: 00007f6d1a333074 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000004000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000006 R14: 00007f6d1a3e9f60 R15: 00007ffc410940d8 syz-executor.0 (3442) used greatest stack depth: 10208 bytes left