============================================
WARNING: possible recursive locking detected
5.15.185-syzkaller #0 Not tainted
--------------------------------------------
kworker/1:11/4356 is trying to acquire lock:
ffff888024e52d88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
ffff888024e52d88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: hsr_dev_xmit+0x130/0x1d0 net/hsr/hsr_device.c:222

but task is already holding lock:
ffff88801ef4cd88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
ffff88801ef4cd88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: hsr_dev_xmit+0x130/0x1d0 net/hsr/hsr_device.c:222

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/1:11/4356:
 #0: ffff88802aeeb538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900033ffd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d22a948 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1520 net/ipv6/addrconf.c:4116
 #3: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
 #4: ffffffff8c11c000 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
 #5: ffffffff8c11c000 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
 #6: ffff88801ef4cd88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
 #6: ffff88801ef4cd88 (&hsr->seqnr_lock){+.-.}-{2:2}, at: hsr_dev_xmit+0x130/0x1d0 net/hsr/hsr_device.c:222
 #7: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
 #8: ffffffff8c11c000 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
 #9: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
 #10: ffffffff8c11c000 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312

stack backtrace:
CPU: 1 PID: 4356 Comm: kworker/1:11 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 __lock_acquire+0x1227/0x7c60 kernel/locking/lockdep.c:-1
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:368 [inline]
 hsr_dev_xmit+0x130/0x1d0 net/hsr/hsr_device.c:222
 __netdev_start_xmit include/linux/netdevice.h:5027 [inline]
 netdev_start_xmit include/linux/netdevice.h:5041 [inline]
 xmit_one net/core/dev.c:3649 [inline]
 dev_hard_start_xmit+0x2a5/0x7e0 net/core/dev.c:3665
 __dev_queue_xmit+0x19df/0x2ed0 net/core/dev.c:4288
 br_dev_queue_push_xmit+0x685/0x820 net/bridge/br_forward.c:53
 NF_HOOK+0x2e0/0x370 include/linux/netfilter.h:302
 br_forward_finish+0x74/0x80 net/bridge/br_forward.c:66
 NF_HOOK+0x2e0/0x370 include/linux/netfilter.h:302
 __br_forward+0x41f/0x600 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 maybe_deliver+0xb5/0x150 net/bridge/br_forward.c:189
 br_flood+0x2fc/0x450 net/bridge/br_forward.c:231
 br_dev_xmit+0xee3/0x1400 net/bridge/br_device.c:-1
 __netdev_start_xmit include/linux/netdevice.h:5027 [inline]
 netdev_start_xmit include/linux/netdevice.h:5041 [inline]
 xmit_one net/core/dev.c:3649 [inline]
 dev_hard_start_xmit+0x2a5/0x7e0 net/core/dev.c:3665
 __dev_queue_xmit+0x19df/0x2ed0 net/core/dev.c:4288
 hsr_xmit net/hsr/hsr_forward.c:338 [inline]
 hsr_forward_do net/hsr/hsr_forward.c:429 [inline]
 hsr_forward_skb+0xfb4/0x16e0 net/hsr/hsr_forward.c:582
 hsr_dev_xmit+0x13b/0x1d0 net/hsr/hsr_device.c:223
 __netdev_start_xmit include/linux/netdevice.h:5027 [inline]
 netdev_start_xmit include/linux/netdevice.h:5041 [inline]
 xmit_one net/core/dev.c:3649 [inline]
 dev_hard_start_xmit+0x2a5/0x7e0 net/core/dev.c:3665
 __dev_queue_xmit+0x19df/0x2ed0 net/core/dev.c:4288
 neigh_output include/net/neighbour.h:509 [inline]
 ip6_finish_output2+0x1070/0x1500 net/ipv6/ip6_output.c:130
 dst_output include/net/dst.h:452 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ndisc_send_skb+0xbea/0x14a0 net/ipv6/ndisc.c:513
 ndisc_send_ns+0x63c/0x840 net/ipv6/ndisc.c:655
 addrconf_dad_work+0xa47/0x1520 net/ipv6/addrconf.c:4204
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>