============================================ WARNING: possible recursive locking detected 6.1.90-syzkaller #0 Not tainted -------------------------------------------- kworker/0:1/14 is trying to acquire lock: ffff0000dd202a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff0000dd202a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3884 [inline] ffff0000dd202a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x1e3c/0x38d8 net/core/dev.c:4259 but task is already holding lock: ffff0000f14bf258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] ffff0000f14bf258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:194 [inline] ffff0000f14bf258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3841 [inline] ffff0000f14bf258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x10b4/0x38d8 net/core/dev.c:4259 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 13 locks held by kworker/0:1/14: #0: ffff0000d547a938 ((wq_completion)mld){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265 #1: ffff800019e77c20 ((work_completion)(&(&idev->mc_ifc_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267 #2: ffff0000d9d59538 (&idev->mc_lock){+.+.}-{3:3}, at: mld_ifc_work+0x3c/0xc20 net/ipv6/mcast.c:2652 #3: ffff800015a14ca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #4: ffff800015a14ca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #5: ffff800015a14d00 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:349 #6: ffff0000f14bf258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #6: ffff0000f14bf258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:194 [inline] #6: ffff0000f14bf258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3841 [inline] #6: ffff0000f14bf258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x10b4/0x38d8 net/core/dev.c:4259 #7: ffff800015a14ca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #8: ffff800015a14d00 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:349 #9: ffff0000d5ce80b0 (k-slock-AF_INET6){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline] #9: ffff0000d5ce80b0 (k-slock-AF_INET6){+.-.}-{2:2}, at: icmpv6_xmit_lock+0xec/0x19c net/ipv6/icmp.c:108 #10: ffff800015a14ca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #11: ffff800015a14ca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349 #12: ffff800015a14d00 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:349 stack backtrace: CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted 6.1.90-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Workqueue: mld mld_ifc_work 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:351 [inline] __dev_xmit_skb net/core/dev.c:3884 [inline] __dev_queue_xmit+0x1e3c/0x38d8 net/core/dev.c:4259 dev_queue_xmit include/linux/netdevice.h:3021 [inline] neigh_connected_output+0x344/0x3d4 net/core/neighbour.c:1592 neigh_output include/net/neighbour.h:544 [inline] ip6_finish_output2+0xdc0/0x1aa8 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 include/net/dst.h:423 [inline] ipip6_tunnel_xmit net/ipv6/sit.c:1039 [inline] sit_tunnel_xmit+0xa88/0x1ee8 net/ipv6/sit.c:1076 __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 qdisc_restart net/sched/sch_generic.c:407 [inline] __qdisc_run+0x904/0x239c net/sched/sch_generic.c:415 __dev_xmit_skb net/core/dev.c:3917 [inline] __dev_queue_xmit+0xe14/0x38d8 net/core/dev.c:4259 dev_queue_xmit include/linux/netdevice.h:3021 [inline] neigh_connected_output+0x344/0x3d4 net/core/neighbour.c:1592 neigh_output include/net/neighbour.h:544 [inline] ip6_finish_output2+0xdc0/0x1aa8 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 ip6tunnel_xmit+0x174/0x460 include/net/ip6_tunnel.h:161 ip6_tnl_xmit+0x1f0c/0x2698 net/ipv6/ip6_tunnel.c:1280 __gre6_xmit+0x7c8/0xadc net/ipv6/ip6_gre.c:809 ip6gre_xmit_ipv6 net/ipv6/ip6_gre.c:865 [inline] ip6gre_tunnel_xmit+0xd8c/0x12fc net/ipv6/ip6_gre.c:937 __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+0x558/0x658 net/core/neighbour.c:1563 neigh_output include/net/neighbour.h:544 [inline] ip6_finish_output2+0xdc0/0x1aa8 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+0x160/0x4f0 include/linux/netfilter.h:302 mld_sendpack+0x90c/0x1364 net/ipv6/mcast.c:1820 mld_send_cr net/ipv6/mcast.c:2121 [inline] mld_ifc_work+0x848/0xc20 net/ipv6/mcast.c:2653 process_one_work+0x7ac/0x1404 kernel/workqueue.c:2292 worker_thread+0x8e4/0xfec kernel/workqueue.c:2439 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864