============================================ WARNING: possible recursive locking detected 6.1.85-syzkaller #0 Not tainted -------------------------------------------- syz-executor.0/21404 is trying to acquire lock: ffff888073bd9458 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff888073bd9458 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4304 [inline] ffff888073bd9458 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1c0/0x5e0 net/sched/sch_generic.c:340 but task is already holding lock: ffff88805853d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88805853d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4304 [inline] ffff88805853d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1c0/0x5e0 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.0/21404: #0: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rawv6_send_hdrinc+0xa8b/0x1850 net/ipv6/raw.c:652 #1: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #1: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #1: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x698/0x1520 net/ipv6/ip6_output.c:119 #2: ffffffff8d12aca0 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #2: ffffffff8d12aca0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #2: ffffffff8d12aca0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2d6/0x3cf0 net/core/dev.c:4216 #3: ffff888051d69258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #3: ffff888051d69258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:194 [inline] #3: ffff888051d69258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3841 [inline] #3: ffff888051d69258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x131b/0x3cf0 net/core/dev.c:4259 #4: ffff88805853d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #4: ffff88805853d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4304 [inline] #4: ffff88805853d0d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x1c0/0x5e0 net/sched/sch_generic.c:340 #5: ffff8880280a07f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #5: ffff8880280a07f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock net/ipv6/icmp.c:108 [inline] #5: ffff8880280a07f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmp6_send+0xc10/0x2160 net/ipv6/icmp.c:543 #6: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #6: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: icmp6_send+0xb70/0x2160 net/ipv6/icmp.c:535 #7: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #7: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #7: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x698/0x1520 net/ipv6/ip6_output.c:119 #8: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #8: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #8: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: ip6_nd_hdr net/ipv6/ndisc.c:452 [inline] #8: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: ndisc_send_skb+0x5a8/0x14e0 net/ipv6/ndisc.c:503 #9: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #9: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #9: ffffffff8d12ac40 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x698/0x1520 net/ipv6/ip6_output.c:119 #10: ffffffff8d12aca0 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #10: ffffffff8d12aca0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #10: ffffffff8d12aca0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2d6/0x3cf0 net/core/dev.c:4216 #11: ffff888057d8d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #11: ffff888057d8d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:194 [inline] #11: ffff888057d8d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3841 [inline] #11: ffff888057d8d258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x131b/0x3cf0 net/core/dev.c:4259 stack backtrace: CPU: 1 PID: 21404 Comm: syz-executor.0 Not tainted 6.1.85-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2983 [inline] check_deadlock kernel/locking/lockdep.c:3026 [inline] validate_chain+0x4711/0x5950 kernel/locking/lockdep.c:3812 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __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:351 [inline] __netif_tx_lock include/linux/netdevice.h:4304 [inline] sch_direct_xmit+0x1c0/0x5e0 net/sched/sch_generic.c:340 __dev_xmit_skb net/core/dev.c:3854 [inline] __dev_queue_xmit+0x1ace/0x3cf0 net/core/dev.c:4259 neigh_output include/net/neighbour.h:544 [inline] ip6_finish_output2+0xedb/0x1520 net/ipv6/ip6_output.c:134 __ip6_finish_output net/ipv6/ip6_output.c:201 [inline] ip6_finish_output+0x6a0/0xa80 net/ipv6/ip6_output.c:212 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xbab/0x14e0 net/ipv6/ndisc.c:509 ndisc_solicit+0x48a/0x690 neigh_probe net/core/neighbour.c:1075 [inline] __neigh_event_send+0xf30/0x1610 net/core/neighbour.c:1242 neigh_event_send_probe include/net/neighbour.h:468 [inline] neigh_event_send include/net/neighbour.h:474 [inline] neigh_resolve_output+0x1b0/0x710 net/core/neighbour.c:1547 neigh_output include/net/neighbour.h:544 [inline] ip6_finish_output2+0xedb/0x1520 net/ipv6/ip6_output.c:134 __ip6_finish_output net/ipv6/ip6_output.c:201 [inline] ip6_finish_output+0x6a0/0xa80 net/ipv6/ip6_output.c:212 ip6_send_skb+0x12b/0x240 net/ipv6/ip6_output.c:1995 icmp6_send+0x166f/0x2160 net/ipv6/icmp.c:622 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x38/0x4e0 net/ipv6/route.c:2789 ip_tunnel_xmit+0x1905/0x2cc0 net/ipv4/ip_tunnel.c:846 __gre_xmit net/ipv4/ip_gre.c:474 [inline] erspan_xmit+0xaa2/0x1530 net/ipv4/ip_gre.c:723 __netdev_start_xmit include/linux/netdevice.h:4853 [inline] netdev_start_xmit include/linux/netdevice.h:4867 [inline] xmit_one net/core/dev.c:3627 [inline] dev_hard_start_xmit+0x261/0x8c0 net/core/dev.c:3643 sch_direct_xmit+0x2b2/0x5e0 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3854 [inline] __dev_queue_xmit+0x1ace/0x3cf0 net/core/dev.c:4259 neigh_output include/net/neighbour.h:544 [inline] ip6_finish_output2+0xedb/0x1520 net/ipv6/ip6_output.c:134 __ip6_finish_output net/ipv6/ip6_output.c:201 [inline] ip6_finish_output+0x6a0/0xa80 net/ipv6/ip6_output.c:212 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] rawv6_send_hdrinc+0xd15/0x1850 net/ipv6/raw.c:654 rawv6_sendmsg+0x1648/0x2150 net/ipv6/raw.c:912 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5a5/0x8f0 net/socket.c:2514 ___sys_sendmsg net/socket.c:2568 [inline] __sys_sendmmsg+0x3ab/0x730 net/socket.c:2654 __do_sys_sendmmsg net/socket.c:2683 [inline] __se_sys_sendmmsg net/socket.c:2680 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2680 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f3af227de69 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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:00007f3af30b10c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f3af23abf80 RCX: 00007f3af227de69 RDX: 0000000000000002 RSI: 0000000020001e80 RDI: 0000000000000003 RBP: 00007f3af22ca47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f3af23abf80 R15: 00007ffe38d43d78 syz-executor.0 (21404) used greatest stack depth: 17848 bytes left