====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/1:0/24 is trying to acquire lock: ffff888055ed8d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline] ffff888055ed8d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4799 [inline] ffff888055ed8d58 (&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: ffff88803cd99030 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline] ffff88803cd99030 (&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:5387 [inline] netdev_start_xmit include/linux/netdevice.h:5396 [inline] xmit_one net/core/dev.c:3889 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3905 __dev_queue_xmit+0x1435/0x37f0 net/core/dev.c:4872 neigh_output include/net/neighbour.h:560 [inline] ip_finish_output2+0xc4b/0x10b0 net/ipv4/ip_output.c:236 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:437 iptunnel_xmit+0x626/0xd10 net/ipv4/ip_tunnel_core.c:97 ip_tunnel_xmit+0x195b/0x2040 net/ipv4/ip_tunnel.c:848 __gre_xmit+0x19e/0x240 net/ipv4/ip_gre.c:491 erspan_xmit+0xad5/0x1590 net/ipv4/ip_gre.c:750 __netdev_start_xmit include/linux/netdevice.h:5387 [inline] netdev_start_xmit include/linux/netdevice.h:5396 [inline] xmit_one net/core/dev.c:3889 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3905 sch_direct_xmit+0x257/0x4c0 net/sched/sch_generic.c:372 __dev_xmit_skb net/core/dev.c:4211 [inline] __dev_queue_xmit+0x1754/0x37f0 net/core/dev.c:4833 dev_queue_xmit include/linux/netdevice.h:3436 [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 bond_alb_monitor+0x3d0/0x17c0 drivers/net/bonding/bond_alb.c:1563 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3478 kthread+0x389/0x470 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 -> #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+0x1520/0x2cd0 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:4799 [inline] sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370 __dev_xmit_skb net/core/dev.c:4211 [inline] __dev_queue_xmit+0x1754/0x37f0 net/core/dev.c:4833 dev_queue_xmit include/linux/netdevice.h:3436 [inline] hsr_xmit net/hsr/hsr_forward.c:440 [inline] hsr_forward_do net/hsr/hsr_forward.c:581 [inline] hsr_forward_skb+0x152a/0x28c0 net/hsr/hsr_forward.c:743 hsr_dev_xmit+0x242/0x360 net/hsr/hsr_device.c:236 __netdev_start_xmit include/linux/netdevice.h:5387 [inline] netdev_start_xmit include/linux/netdevice.h:5396 [inline] xmit_one net/core/dev.c:3889 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3905 __dev_queue_xmit+0x1435/0x37f0 net/core/dev.c:4872 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x337/0x540 net/ipv6/ip6_output.c:246 dst_output include/net/dst.h:471 [inline] NF_HOOK+0x177/0x4f0 include/linux/netfilter.h:318 mld_sendpack+0x890/0xe10 net/ipv6/mcast.c:1853 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x839/0xe70 net/ipv6/mcast.c:2694 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3478 kthread+0x389/0x470 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/1:0/24: #0: ffff888031f27d40 ((wq_completion)mld){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff888031f27d40 ((wq_completion)mld){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #1: ffffc900001e7c40 ((work_completion)(&(&idev->mc_ifc_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #1: ffffc900001e7c40 ((work_completion)(&(&idev->mc_ifc_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3397 #2: ffff888067767530 (&idev->mc_lock){+.+.}-{4:4}, at: mld_ifc_work+0x2d/0xe70 net/ipv6/mcast.c:2693 #3: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #3: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #3: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: mld_sendpack+0x206/0xe10 net/ipv6/mcast.c:1825 #4: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #4: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #4: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x11e/0x540 net/ipv6/ip6_output.c:234 #5: ffffffff8e95c7e0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #5: ffffffff8e95c7e0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline] #5: ffffffff8e95c7e0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x29b/0x37f0 net/core/dev.c:4793 #6: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #6: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #6: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229 #7: ffff88803cd99030 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline] #7: ffff88803cd99030 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235 #8: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #8: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #8: ffffffff8e95c780 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0xb3/0x28c0 net/hsr/hsr_forward.c:738 #9: ffffffff8e95c7e0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #9: ffffffff8e95c7e0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline] #9: ffffffff8e95c7e0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x29b/0x37f0 net/core/dev.c:4793 #10: ffff888094925228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#4){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:354 [inline] #10: ffff888094925228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#4){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline] #10: ffff888094925228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#4){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4198 [inline] #10: ffff888094925228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#4){+...}-{3:3}, at: __dev_queue_xmit+0x112b/0x37f0 net/core/dev.c:4833 stack backtrace: CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 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+0x1520/0x2cd0 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:4799 [inline] sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370 __dev_xmit_skb net/core/dev.c:4211 [inline] __dev_queue_xmit+0x1754/0x37f0 net/core/dev.c:4833 dev_queue_xmit include/linux/netdevice.h:3436 [inline] hsr_xmit net/hsr/hsr_forward.c:440 [inline] hsr_forward_do net/hsr/hsr_forward.c:581 [inline] hsr_forward_skb+0x152a/0x28c0 net/hsr/hsr_forward.c:743 hsr_dev_xmit+0x242/0x360 net/hsr/hsr_device.c:236 __netdev_start_xmit include/linux/netdevice.h:5387 [inline] netdev_start_xmit include/linux/netdevice.h:5396 [inline] xmit_one net/core/dev.c:3889 [inline] dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3905 __dev_queue_xmit+0x1435/0x37f0 net/core/dev.c:4872 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x337/0x540 net/ipv6/ip6_output.c:246 dst_output include/net/dst.h:471 [inline] NF_HOOK+0x177/0x4f0 include/linux/netfilter.h:318 mld_sendpack+0x890/0xe10 net/ipv6/mcast.c:1853 mld_send_cr net/ipv6/mcast.c:2154 [inline] mld_ifc_work+0x839/0xe70 net/ipv6/mcast.c:2694 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3478 kthread+0x389/0x470 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