====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/1:5/5735 is trying to acquire lock: ffff8880a7ad5958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline] ffff8880a7ad5958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4781 [inline] ffff8880a7ad5958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370 but task is already holding lock: ffff888093d1cff0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline] ffff888093d1cff0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&hsr->seqnr_lock){+.-.}-{3:3}: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:182 spin_lock_bh include/linux/spinlock.h:348 [inline] hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235 __netdev_start_xmit include/linux/netdevice.h:5368 [inline] netdev_start_xmit include/linux/netdevice.h:5377 [inline] xmit_one net/core/dev.c:3888 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904 __dev_queue_xmit+0x14d9/0x3950 net/core/dev.c:4870 NF_HOOK+0x33a/0x3c0 include/linux/netfilter.h:-1 arp_xmit+0x16c/0x270 net/ipv4/arp.c:665 arp_solicit+0xbe0/0xe40 net/ipv4/arp.c:392 neigh_probe net/core/neighbour.c:1096 [inline] __neigh_event_send+0xf05/0x14d0 net/core/neighbour.c:1276 neigh_event_send_probe include/net/neighbour.h:480 [inline] neigh_event_send include/net/neighbour.h:486 [inline] neigh_resolve_output+0x198/0x750 net/core/neighbour.c:1603 neigh_output include/net/neighbour.h:556 [inline] ip_finish_output2+0xca9/0x1070 net/ipv4/ip_output.c:237 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:438 iptunnel_xmit+0x621/0xd10 net/ipv4/ip_tunnel_core.c:97 ip_tunnel_xmit+0x193a/0x1f20 net/ipv4/ip_tunnel.c:845 __gre_xmit+0x19e/0x240 net/ipv4/ip_gre.c:491 erspan_xmit+0xa41/0x14d0 net/ipv4/ip_gre.c:750 __netdev_start_xmit include/linux/netdevice.h:5368 [inline] netdev_start_xmit include/linux/netdevice.h:5377 [inline] xmit_one net/core/dev.c:3888 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904 sch_direct_xmit+0x251/0x4c0 net/sched/sch_generic.c:372 __dev_xmit_skb net/core/dev.c:4209 [inline] __dev_queue_xmit+0x180f/0x3950 net/core/dev.c:4831 dev_queue_xmit include/linux/netdevice.h:3418 [inline] alb_send_lp_vid+0x348/0x550 drivers/net/bonding/bond_alb.c:949 alb_send_learning_packets+0x12c/0x300 drivers/net/bonding/bond_alb.c:1012 alb_fasten_mac_swap+0x639/0xf60 drivers/net/bonding/bond_alb.c:1076 bond_alb_handle_active_change+0xc6d/0xf30 drivers/net/bonding/bond_alb.c:1774 bond_change_active_slave+0x106e/0x35f0 drivers/net/bonding/bond_main.c:1305 bond_select_active_slave+0x909/0xd40 drivers/net/bonding/bond_main.c:1375 bond_enslave+0x2299/0x3c10 drivers/net/bonding/bond_main.c:2286 do_set_master+0x533/0x6d0 net/core/rtnetlink.c:2986 rtnl_newlink_create+0x6af/0xb70 net/core/rtnetlink.c:3878 __rtnl_newlink net/core/rtnetlink.c:3995 [inline] rtnl_newlink+0x166a/0x1bb0 net/core/rtnetlink.c:4110 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6996 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2698 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752 __sys_sendmsg net/socket.c:2784 [inline] __do_sys_sendmsg net/socket.c:2789 [inline] __se_sys_sendmsg net/socket.c:2787 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2787 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158 spin_lock include/linux/spinlock.h:342 [inline] __netif_tx_lock include/linux/netdevice.h:4781 [inline] sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370 __dev_xmit_skb net/core/dev.c:4209 [inline] __dev_queue_xmit+0x180f/0x3950 net/core/dev.c:4831 dev_queue_xmit include/linux/netdevice.h:3418 [inline] hsr_xmit net/hsr/hsr_forward.c:440 [inline] hsr_forward_do net/hsr/hsr_forward.c:581 [inline] hsr_forward_skb+0x167e/0x2a80 net/hsr/hsr_forward.c:743 hsr_dev_xmit+0x242/0x360 net/hsr/hsr_device.c:236 __netdev_start_xmit include/linux/netdevice.h:5368 [inline] netdev_start_xmit include/linux/netdevice.h:5377 [inline] xmit_one net/core/dev.c:3888 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904 __dev_queue_xmit+0x14d9/0x3950 net/core/dev.c:4870 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x340/0x550 net/ipv6/ip6_output.c:246 dst_output include/net/dst.h:470 [inline] NF_HOOK+0x177/0x4f0 include/linux/netfilter.h:318 mld_sendpack+0x8b4/0xe40 net/ipv6/mcast.c:1855 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x835/0xe70 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3302 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&hsr->seqnr_lock); lock(&qdisc_xmit_lock_key#4); lock(&hsr->seqnr_lock); lock(&qdisc_xmit_lock_key#4); *** DEADLOCK *** 11 locks held by kworker/1:5/5735: #0: ffff888031eb4d40 ((wq_completion)mld){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline] #0: ffff888031eb4d40 ((wq_completion)mld){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385 #1: ffffc90004e17c40 ((work_completion)(&(&idev->mc_ifc_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline] #1: ffffc90004e17c40 ((work_completion)(&(&idev->mc_ifc_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385 #2: ffff8880b0e64530 (&idev->mc_lock){+.+.}-{4:4}, at: mld_ifc_work+0x2d/0xe70 net/ipv6/mcast.c:2692 #3: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #3: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #3: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: mld_sendpack+0x213/0xe40 net/ipv6/mcast.c:1827 #4: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #4: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #4: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x126/0x550 net/ipv6/ip6_output.c:234 #5: ffffffff8e95cdc0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #5: ffffffff8e95cdc0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline] #5: ffffffff8e95cdc0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2b6/0x3950 net/core/dev.c:4791 #6: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #6: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #6: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229 #7: ffff888093d1cff0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline] #7: ffff888093d1cff0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235 #8: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #8: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #8: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0xbb/0x2a80 net/hsr/hsr_forward.c:738 #9: ffffffff8e95cdc0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #9: ffffffff8e95cdc0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline] #9: ffffffff8e95cdc0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2b6/0x3950 net/core/dev.c:4791 #10: ffff88806a1e3228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:354 [inline] #10: ffff88806a1e3228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline] #10: ffff88806a1e3228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4196 [inline] #10: ffff88806a1e3228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x11a6/0x3950 net/core/dev.c:4831 stack backtrace: CPU: 1 UID: 0 PID: 5735 Comm: kworker/1:5 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: mld mld_ifc_work Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158 spin_lock include/linux/spinlock.h:342 [inline] __netif_tx_lock include/linux/netdevice.h:4781 [inline] sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370 __dev_xmit_skb net/core/dev.c:4209 [inline] __dev_queue_xmit+0x180f/0x3950 net/core/dev.c:4831 dev_queue_xmit include/linux/netdevice.h:3418 [inline] hsr_xmit net/hsr/hsr_forward.c:440 [inline] hsr_forward_do net/hsr/hsr_forward.c:581 [inline] hsr_forward_skb+0x167e/0x2a80 net/hsr/hsr_forward.c:743 hsr_dev_xmit+0x242/0x360 net/hsr/hsr_device.c:236 __netdev_start_xmit include/linux/netdevice.h:5368 [inline] netdev_start_xmit include/linux/netdevice.h:5377 [inline] xmit_one net/core/dev.c:3888 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904 __dev_queue_xmit+0x14d9/0x3950 net/core/dev.c:4870 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x340/0x550 net/ipv6/ip6_output.c:246 dst_output include/net/dst.h:470 [inline] NF_HOOK+0x177/0x4f0 include/linux/netfilter.h:318 mld_sendpack+0x8b4/0xe40 net/ipv6/mcast.c:1855 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x835/0xe70 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3302 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245