============================================ WARNING: possible recursive locking detected 6.1.74-syzkaller #0 Not tainted -------------------------------------------- syz-executor.3/8276 is trying to acquire lock: ffff000113d90458 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff000113d90458 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4304 [inline] ffff000113d90458 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x164/0x548 net/sched/sch_generic.c:340 but task is already holding lock: ffff0000c386ecd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff0000c386ecd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4304 [inline] ffff0000c386ecd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x164/0x548 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.3/8276: #0: ffff800015a04ce0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:305 #1: ffff800015a04ce0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:305 #2: ffff800015a04d40 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:305 #3: ffff0000d268e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:360 [inline] #3: ffff0000d268e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:194 [inline] #3: ffff0000d268e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3841 [inline] #3: ffff0000d268e258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x10b4/0x38d8 net/core/dev.c:4259 #4: ffff0000c386ecd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #4: ffff0000c386ecd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock include/linux/netdevice.h:4304 [inline] #4: ffff0000c386ecd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x164/0x548 net/sched/sch_generic.c:340 #5: ffff0000d59e00b0 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:360 [inline] #5: ffff0000d59e00b0 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock+0xec/0x19c net/ipv6/icmp.c:108 #6: ffff800015a04ce0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:305 #7: ffff800015a04ce0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:305 #8: ffff800015a04ce0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:305 #9: ffff800015a04ce0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:305 #10: ffff800015a04d40 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:305 #11: ffff0000de981258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:360 [inline] #11: ffff0000de981258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:194 [inline] #11: ffff0000de981258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3841 [inline] #11: ffff0000de981258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x10b4/0x38d8 net/core/dev.c:4259 stack backtrace: CPU: 0 PID: 8276 Comm: syz-executor.3 Not tainted 6.1.74-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 Call trace: dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 __lock_acquire+0x6310/0x7680 kernel/locking/lockdep.c:5049 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x54/0x6c kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:350 [inline] __netif_tx_lock include/linux/netdevice.h:4304 [inline] sch_direct_xmit+0x164/0x548 net/sched/sch_generic.c:340 __dev_xmit_skb net/core/dev.c:3854 [inline] __dev_queue_xmit+0x1658/0x38d8 net/core/dev.c:4259 dev_queue_xmit include/linux/netdevice.h:3021 [inline] neigh_resolve_output+0x518/0x618 net/core/neighbour.c:1563 neigh_output include/net/neighbour.h:544 [inline] ip6_finish_output2+0xdac/0x1a88 net/ipv6/ip6_output.c:134 __ip6_finish_output net/ipv6/ip6_output.c:201 [inline] ip6_finish_output+0x5a4/0x940 net/ipv6/ip6_output.c:212 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:233 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xc38/0x179c net/ipv6/ndisc.c:509 ndisc_solicit+0x3ac/0x590 neigh_probe+0xc4/0x128 net/core/neighbour.c:1075 __neigh_event_send+0xe50/0x1668 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+0x17c/0x618 net/core/neighbour.c:1547 neigh_output include/net/neighbour.h:544 [inline] ip6_finish_output2+0xdac/0x1a88 net/ipv6/ip6_output.c:134 __ip6_finish_output net/ipv6/ip6_output.c:201 [inline] ip6_finish_output+0x5a4/0x940 net/ipv6/ip6_output.c:212 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:233 dst_output include/net/dst.h:444 [inline] ip6_local_out+0x120/0x160 net/ipv6/output_core.c:161 ip6_send_skb+0x118/0x428 net/ipv6/ip6_output.c:1995 ip6_push_pending_frames+0xd0/0x118 net/ipv6/ip6_output.c:2015 icmpv6_push_pending_frames+0x288/0x3f4 net/ipv6/icmp.c:303 icmp6_send+0x11a8/0x1b2c net/ipv6/icmp.c:622 __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:2789 dst_link_failure+0x11c/0x160 include/net/dst.h:423 ip_tunnel_xmit+0x1e1c/0x28f4 net/ipv4/ip_tunnel.c:819 __gre_xmit net/ipv4/ip_gre.c:469 [inline] erspan_xmit+0x9c8/0x1498 net/ipv4/ip_gre.c:718 __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+0x25c/0x9a4 net/core/dev.c:3643 sch_direct_xmit+0x234/0x548 net/sched/sch_generic.c:342 __dev_xmit_skb net/core/dev.c:3854 [inline] __dev_queue_xmit+0x1658/0x38d8 net/core/dev.c:4259 dev_queue_xmit include/linux/netdevice.h:3021 [inline] neigh_resolve_output+0x518/0x618 net/core/neighbour.c:1563 neigh_output include/net/neighbour.h:544 [inline] ip6_finish_output2+0xdac/0x1a88 net/ipv6/ip6_output.c:134 __ip6_finish_output net/ipv6/ip6_output.c:201 [inline] ip6_finish_output+0x5a4/0x940 net/ipv6/ip6_output.c:212 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:233 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] rawv6_send_hdrinc+0xd74/0x1bfc net/ipv6/raw.c:654 rawv6_sendmsg+0x1114/0x1bc0 net/ipv6/raw.c:912 inet_sendmsg+0x15c/0x290 net/ipv4/af_inet.c:836 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] sock_write_iter+0x2d8/0x414 net/socket.c:1143 call_write_iter include/linux/fs.h:2249 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x610/0x914 fs/read_write.c:584 ksys_write+0x15c/0x26c fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585