============================================ WARNING: possible recursive locking detected 6.8.0-rc7-syzkaller-g707081b61156 #0 Not tainted -------------------------------------------- syz-executor.3/8623 is trying to acquire lock: ffff0000ce4238d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff0000ce4238d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4443 [inline] ffff0000ce4238d8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x1160/0x329c net/core/dev.c:4347 but task is already holding lock: ffff0000eb02dcd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff0000eb02dcd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4443 [inline] ffff0000eb02dcd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x170/0x57c 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 11 locks held by syz-executor.3/8623: #0: ffff80008ee74ac0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:297 #1: ffff80008ee74ac0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:297 #2: ffff80008ee74b20 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:297 #3: ffff0000c8b03258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #3: ffff0000c8b03258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline] #3: ffff0000c8b03258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3763 [inline] #3: ffff0000c8b03258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0xf14/0x329c net/core/dev.c:4317 #4: ffff0000eb02dcd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #4: ffff0000eb02dcd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4443 [inline] #4: ffff0000eb02dcd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x170/0x57c net/sched/sch_generic.c:340 #5: ffff0000d26107f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #5: ffff0000d26107f0 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock+0xec/0x198 net/ipv6/icmp.c:108 #6: ffff80008ee74ac0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:297 #7: ffff80008ee74ac0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:297 #8: ffff80008ee74ac0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:297 #9: ffff80008ee74ac0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:297 #10: ffff80008ee74b20 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:297 stack backtrace: CPU: 1 PID: 8623 Comm: syz-executor.3 Not tainted 6.8.0-rc7-syzkaller-g707081b61156 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 dump_stack+0x1c/0x28 lib/dump_stack.c:113 print_deadlock_bug+0x4e4/0x660 kernel/locking/lockdep.c:3012 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain kernel/locking/lockdep.c:3856 [inline] __lock_acquire+0x5fe4/0x763c kernel/locking/lockdep.c:5137 lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __netif_tx_lock include/linux/netdevice.h:4443 [inline] __dev_queue_xmit+0x1160/0x329c net/core/dev.c:4347 dev_queue_xmit include/linux/netdevice.h:3171 [inline] neigh_resolve_output+0x518/0x618 net/core/neighbour.c:1563 neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0x1038/0x1ec8 net/ipv6/ip6_output.c:137 ip6_finish_output+0x428/0x7a0 net/ipv6/ip6_output.c:222 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:243 dst_output include/net/dst.h:451 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] ndisc_send_skb+0xaa8/0x14f0 net/ipv6/ndisc.c:509 ndisc_solicit+0x3b0/0x594 neigh_probe+0xc4/0x128 net/core/neighbour.c:1075 __neigh_event_send+0xddc/0x1548 net/core/neighbour.c:1242 neigh_event_send_probe include/net/neighbour.h:466 [inline] neigh_event_send include/net/neighbour.h:472 [inline] neigh_resolve_output+0x17c/0x618 net/core/neighbour.c:1547 neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0x1038/0x1ec8 net/ipv6/ip6_output.c:137 ip6_finish_output+0x428/0x7a0 net/ipv6/ip6_output.c:222 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:243 dst_output include/net/dst.h:451 [inline] ip6_local_out+0x120/0x160 net/ipv6/output_core.c:155 ip6_send_skb+0x11c/0x42c net/ipv6/ip6_output.c:1955 ip6_push_pending_frames+0xd0/0x118 net/ipv6/ip6_output.c:1975 icmpv6_push_pending_frames+0x288/0x3f4 net/ipv6/icmp.c:307 icmp6_send+0x1110/0x19f0 net/ipv6/icmp.c:624 __icmpv6_send include/linux/icmpv6.h:28 [inline] icmpv6_send include/linux/icmpv6.h:49 [inline] ip6_link_failure+0x44/0x4a8 net/ipv6/route.c:2787 dst_link_failure+0x11c/0x160 include/net/dst.h:430 ip_tunnel_xmit+0x1b0c/0x2630 net/ipv4/ip_tunnel.c:851 __gre_xmit+0x104/0x198 net/ipv4/ip_gre.c:469 erspan_xmit+0x928/0x13a0 net/ipv4/ip_gre.c:720 __netdev_start_xmit include/linux/netdevice.h:4980 [inline] netdev_start_xmit include/linux/netdevice.h:4994 [inline] xmit_one net/core/dev.c:3547 [inline] dev_hard_start_xmit+0x240/0x8ac net/core/dev.c:3563 sch_direct_xmit+0x244/0x57c net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3776 [inline] __dev_queue_xmit+0x13c0/0x329c net/core/dev.c:4317 dev_queue_xmit include/linux/netdevice.h:3171 [inline] neigh_resolve_output+0x518/0x618 net/core/neighbour.c:1563 neigh_output include/net/neighbour.h:542 [inline] ip6_finish_output2+0x1038/0x1ec8 net/ipv6/ip6_output.c:137 ip6_finish_output+0x428/0x7a0 net/ipv6/ip6_output.c:222 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:243 dst_output include/net/dst.h:451 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] rawv6_send_hdrinc+0xb90/0x18a4 net/ipv6/raw.c:655 rawv6_sendmsg+0x1288/0x1be8 net/ipv6/raw.c:908 inet_sendmsg+0x15c/0x290 net/ipv4/af_inet.c:850 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] sock_write_iter+0x2d8/0x448 net/socket.c:1160 call_write_iter include/linux/fs.h:2087 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0x968/0xc3c fs/read_write.c:590 ksys_write+0x15c/0x26c fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:652 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598