============================================ WARNING: possible recursive locking detected 6.1.135-syzkaller #0 Not tainted -------------------------------------------- kworker/1:2/13181 is trying to acquire lock: ffff888076d66d88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff888076d66d88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: hsr_dev_xmit+0x12e/0x200 net/hsr/hsr_device.c:219 but task is already holding lock: ffff888077c60d88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff888077c60d88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: hsr_dev_xmit+0x12e/0x200 net/hsr/hsr_device.c:219 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&hsr->seqnr_lock); lock(&hsr->seqnr_lock); *** DEADLOCK *** May be due to missing lock nesting notation 11 locks held by kworker/1:2/13181: #0: ffff88802f7b2d38 ((wq_completion)mld){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90003257d00 ((work_completion)(&(&idev->mc_ifc_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #2: ffff88807318b538 (&idev->mc_lock){+.+.}-{3:3}, at: mld_ifc_work+0x29/0xb40 net/ipv6/mcast.c:2658 #3: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #3: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: mld_sendpack+0x1f7/0xe80 net/ipv6/mcast.c:1798 #4: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #4: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #4: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x593/0x1590 net/ipv6/ip6_output.c:123 #5: ffffffff8c92aa40 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #5: ffffffff8c92aa40 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #5: ffffffff8c92aa40 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x26f/0x3760 net/core/dev.c:4257 #6: ffff888077c60d88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #6: ffff888077c60d88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: hsr_dev_xmit+0x12e/0x200 net/hsr/hsr_device.c:219 #7: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #7: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #7: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: hsr_forward_skb+0x98/0x20d0 net/hsr/hsr_forward.c:619 #8: ffffffff8c92aa40 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #8: ffffffff8c92aa40 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #8: ffffffff8c92aa40 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x26f/0x3760 net/core/dev.c:4257 #9: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #9: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #9: ffffffff8c92a9e0 (rcu_read_lock){....}-{1:2}, at: br_dev_xmit+0x176/0x16e0 net/bridge/br_device.c:49 #10: ffffffff8c92aa40 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #10: ffffffff8c92aa40 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #10: ffffffff8c92aa40 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x26f/0x3760 net/core/dev.c:4257 stack backtrace: CPU: 1 PID: 13181 Comm: kworker/1:2 Not tainted 6.1.135-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Workqueue: mld mld_ifc_work Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 __lock_acquire+0x122f/0x7c50 kernel/locking/lockdep.c:-1 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] hsr_dev_xmit+0x12e/0x200 net/hsr/hsr_device.c:219 __netdev_start_xmit include/linux/netdevice.h:4896 [inline] netdev_start_xmit include/linux/netdevice.h:4910 [inline] xmit_one net/core/dev.c:3658 [inline] dev_hard_start_xmit+0x262/0x870 net/core/dev.c:3674 __dev_queue_xmit+0x1bf1/0x3760 net/core/dev.c:4334 dev_queue_xmit include/linux/netdevice.h:3051 [inline] br_dev_queue_push_xmit+0x6a2/0x850 net/bridge/br_forward.c:53 NF_HOOK+0x33c/0x3d0 include/linux/netfilter.h:302 br_forward_finish+0xcf/0x120 net/bridge/br_forward.c:66 NF_HOOK+0x33c/0x3d0 include/linux/netfilter.h:302 __br_forward+0x41f/0x600 net/bridge/br_forward.c:115 br_dev_xmit+0x104a/0x16e0 net/bridge/br_device.c:105 __netdev_start_xmit include/linux/netdevice.h:4896 [inline] netdev_start_xmit include/linux/netdevice.h:4910 [inline] xmit_one net/core/dev.c:3658 [inline] dev_hard_start_xmit+0x262/0x870 net/core/dev.c:3674 __dev_queue_xmit+0x1bf1/0x3760 net/core/dev.c:4334 dev_queue_xmit include/linux/netdevice.h:3051 [inline] hsr_xmit net/hsr/hsr_forward.c:380 [inline] hsr_forward_do net/hsr/hsr_forward.c:471 [inline] hsr_forward_skb+0x12f4/0x20d0 net/hsr/hsr_forward.c:624 hsr_dev_xmit+0x139/0x200 net/hsr/hsr_device.c:220 __netdev_start_xmit include/linux/netdevice.h:4896 [inline] netdev_start_xmit include/linux/netdevice.h:4910 [inline] xmit_one net/core/dev.c:3658 [inline] dev_hard_start_xmit+0x262/0x870 net/core/dev.c:3674 __dev_queue_xmit+0x1bf1/0x3760 net/core/dev.c:4334 neigh_output include/net/neighbour.h:544 [inline] ip6_finish_output2+0xda2/0x1590 net/ipv6/ip6_output.c:138 __ip6_finish_output net/ipv6/ip6_output.c:205 [inline] ip6_finish_output+0x5d3/0xa60 net/ipv6/ip6_output.c:216 dst_output include/net/dst.h:453 [inline] NF_HOOK+0x15d/0x460 include/linux/netfilter.h:302 mld_sendpack+0x893/0xe80 net/ipv6/mcast.c:1826 mld_send_cr net/ipv6/mcast.c:2127 [inline] mld_ifc_work+0x836/0xb40 net/ipv6/mcast.c:2659 process_one_work+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 lo speed is unknown, defaulting to 1000