============================================ WARNING: possible recursive locking detected 6.7.0-syzkaller-12263-gdbc153fd3c14 #0 Not tainted -------------------------------------------- syz-executor.2/10770 is trying to acquire lock: ffff88804262c218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88804262c218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3806 [inline] ffff88804262c218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x2f86/0x3ed0 net/core/dev.c:4317 but task is already holding lock: ffff8880217ac258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] ffff8880217ac258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] ffff8880217ac258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:192 [inline] ffff8880217ac258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3763 [inline] ffff8880217ac258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x108c/0x3ed0 net/core/dev.c:4317 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); *** DEADLOCK *** May be due to missing lock nesting notation 8 locks held by syz-executor.2/10770: #0: ffffffff8d1acba0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #0: ffffffff8d1acba0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #0: ffffffff8d1acba0 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x3b4/0x1820 net/ipv6/ip6_output.c:122 #1: ffffffff8d1acb40 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #1: ffffffff8d1acb40 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline] #1: ffffffff8d1acb40 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x244/0x3ed0 net/core/dev.c:4276 #2: ffff8880217ac258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #2: ffff8880217ac258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #2: ffff8880217ac258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:192 [inline] #2: ffff8880217ac258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3763 [inline] #2: ffff8880217ac258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x108c/0x3ed0 net/core/dev.c:4317 #3: ffff8880211bbcd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #3: ffff8880211bbcd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4452 [inline] #3: ffff8880211bbcd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x333/0xc20 net/sched/sch_generic.c:340 #4: ffff888029c587f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #4: ffff888029c587f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock net/ipv6/icmp.c:108 [inline] #4: ffff888029c587f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmp6_send+0xfb4/0x2b00 net/ipv6/icmp.c:545 #5: ffffffff8d1acba0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #5: ffffffff8d1acba0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #5: ffffffff8d1acba0 (rcu_read_lock){....}-{1:2}, at: icmp6_send+0x16da/0x2b00 net/ipv6/icmp.c:613 #6: ffffffff8d1acba0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #6: ffffffff8d1acba0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #6: ffffffff8d1acba0 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x3b4/0x1820 net/ipv6/ip6_output.c:122 #7: ffffffff8d1acb40 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #7: ffffffff8d1acb40 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline] #7: ffffffff8d1acb40 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x244/0x3ed0 net/core/dev.c:4276 stack backtrace: CPU: 1 PID: 10770 Comm: syz-executor.2 Not tainted 6.7.0-syzkaller-12263-gdbc153fd3c14 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x210a/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5719 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __dev_xmit_skb net/core/dev.c:3806 [inline] __dev_queue_xmit+0x2f86/0x3ed0 net/core/dev.c:4317 dev_queue_xmit include/linux/netdevice.h:3171 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip6_finish_output2+0x10ae/0x1820 net/ipv6/ip6_output.c:137 __ip6_finish_output net/ipv6/ip6_output.c:211 [inline] ip6_finish_output+0x3c7/0xf70 net/ipv6/ip6_output.c:222 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x1e2/0x530 net/ipv6/ip6_output.c:243 dst_output include/net/dst.h:451 [inline] ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:155 ip6_send_skb+0xcd/0x2d0 net/ipv6/ip6_output.c:1952 ip6_push_pending_frames+0xe0/0x100 net/ipv6/ip6_output.c:1972 icmpv6_push_pending_frames+0x2da/0x470 net/ipv6/icmp.c:307 icmp6_send+0x1d91/0x2b00 net/ipv6/icmp.c:624 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x31/0x5a0 net/ipv6/route.c:2787 dst_link_failure include/net/dst.h:430 [inline] ip_tunnel_xmit+0x2d75/0x33b0 net/ipv4/ip_tunnel.c:837 erspan_xmit+0x51f/0x1bf0 net/ipv4/ip_gre.c:720 __netdev_start_xmit include/linux/netdevice.h:4989 [inline] netdev_start_xmit include/linux/netdevice.h:5003 [inline] xmit_one net/core/dev.c:3547 [inline] dev_hard_start_xmit+0x137/0x6d0 net/core/dev.c:3563 sch_direct_xmit+0x1ac/0xc20 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3776 [inline] __dev_queue_xmit+0x12b0/0x3ed0 net/core/dev.c:4317 dev_queue_xmit include/linux/netdevice.h:3171 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip6_finish_output2+0x10ae/0x1820 net/ipv6/ip6_output.c:137 __ip6_finish_output net/ipv6/ip6_output.c:211 [inline] ip6_finish_output+0x3c7/0xf70 net/ipv6/ip6_output.c:222 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x1e2/0x530 net/ipv6/ip6_output.c:243 dst_output include/net/dst.h:451 [inline] ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:155 ip6_send_skb+0xcd/0x2d0 net/ipv6/ip6_output.c:1952 udp_v6_send_skb+0x9a6/0x1960 net/ipv6/udp.c:1285 udpv6_sendmsg+0x24ed/0x2fe0 net/ipv6/udp.c:1580 inet6_sendmsg+0x9d/0xe0 net/ipv6/af_inet6.c:657 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0xd5/0x180 net/socket.c:745 ____sys_sendmsg+0x2ac/0x940 net/socket.c:2584 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2638 __sys_sendmmsg+0x1a1/0x450 net/socket.c:2724 __do_sys_sendmmsg net/socket.c:2753 [inline] __se_sys_sendmmsg net/socket.c:2750 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2750 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd3/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f4bf1a7cda9 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:00007f4bf28290c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f4bf1babf80 RCX: 00007f4bf1a7cda9 RDX: 040000000000021e RSI: 0000000020003280 RDI: 0000000000000003 RBP: 00007f4bf1ac947a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f4bf1babf80 R15: 00007ffd010fc648