============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.4503/23574 is trying to acquire lock:
ffff888095478fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline]
ffff888095478fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235

but task is already holding lock:
ffff888064ae4fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline]
ffff888064ae4fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330

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 syz.0.4503/23574:
 #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #0: ffffffff8fdceac0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4107
 #1: ffffc90000a08ce0 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd4/0x5e0 kernel/time/timer.c:1745
 #2: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #2: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #2: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: hsr_announce+0x89/0x370 net/hsr/hsr_device.c:419
 #3: ffff888064ae4fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline]
 #3: ffff888064ae4fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330
 #4: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #4: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #4: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0xbb/0x2a80 net/hsr/hsr_forward.c:738
 #5: ffffffff8e95d080 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
 #5: ffffffff8e95d080 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline]
 #5: ffffffff8e95d080 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2b6/0x3950 net/core/dev.c:4791
 #6: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #6: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #6: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: bond_start_xmit+0xb4/0x1900 drivers/net/bonding/bond_main.c:5589
 #7: ffffffff8e95d080 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
 #7: ffffffff8e95d080 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline]
 #7: ffffffff8e95d080 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2b6/0x3950 net/core/dev.c:4791
 #8: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #8: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #8: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x193/0x1990 net/bridge/br_device.c:52
 #9: ffffffff8e95d080 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
 #9: ffffffff8e95d080 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline]
 #9: ffffffff8e95d080 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2b6/0x3950 net/core/dev.c:4791
 #10: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #10: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #10: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229

stack backtrace:
CPU: 1 UID: 0 PID: 23574 Comm: syz.0.4503 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_deadlock_bug+0x279/0x290 kernel/locking/lockdep.c:3041
 check_deadlock kernel/locking/lockdep.c:3093 [inline]
 validate_chain kernel/locking/lockdep.c:3895 [inline]
 __lock_acquire+0x253f/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 __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:5343 [inline]
 netdev_start_xmit include/linux/netdevice.h:5352 [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
 dev_queue_xmit include/linux/netdevice.h:3401 [inline]
 br_dev_queue_push_xmit+0x370/0x4b0 net/bridge/br_forward.c:53
 NF_HOOK+0x360/0x3f0 include/linux/netfilter.h:318
 br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66
 NF_HOOK+0x360/0x3f0 include/linux/netfilter.h:318
 __br_forward+0x397/0x540 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 maybe_deliver net/bridge/br_forward.c:191 [inline]
 br_flood+0x6ee/0xb80 net/bridge/br_forward.c:238
 br_dev_xmit+0x12bd/0x1990 net/bridge/br_device.c:108
 __netdev_start_xmit include/linux/netdevice.h:5343 [inline]
 netdev_start_xmit include/linux/netdevice.h:5352 [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
 __bond_start_xmit drivers/net/bonding/bond_main.c:-1 [inline]
 bond_start_xmit+0xd5c/0x1900 drivers/net/bonding/bond_main.c:5591
 __netdev_start_xmit include/linux/netdevice.h:5343 [inline]
 netdev_start_xmit include/linux/netdevice.h:5352 [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
 dev_queue_xmit include/linux/netdevice.h:3401 [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
 send_hsr_supervision_frame+0x731/0xcb0 net/hsr/hsr_device.c:364
 hsr_announce+0x1db/0x370 net/hsr/hsr_device.c:421
 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x22a/0x840 kernel/softirq.c:622
 do_softirq+0x76/0xd0 kernel/softirq.c:523
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 hsr_dev_close+0xa4/0x130 net/hsr/hsr_device.c:181
 __dev_close_many+0x36d/0x6e0 net/core/dev.c:1776
 __dev_close net/core/dev.c:1788 [inline]
 __dev_change_flags+0x2cb/0x690 net/core/dev.c:9808
 netif_change_flags+0x88/0x1a0 net/core/dev.c:9873
 do_setlink+0xf82/0x4590 net/core/rtnetlink.c:3180
 rtnl_group_changelink net/core/rtnetlink.c:3812 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3980 [inline]
 rtnl_newlink+0x14ca/0x1bb0 net/core/rtnetlink.c:4108
 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6994
 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
RIP: 0033:0x7f13bd99c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f13be8fc028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f13bdc15fa0 RCX: 00007f13bd99c819
RDX: 0000000000008024 RSI: 0000200000000140 RDI: 0000000000000003
RBP: 00007f13bda32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f13bdc16038 R14: 00007f13bdc15fa0 R15: 00007ffd58f2b6f8
 </TASK>
lec0: NETDEV WATCHDOG: CPU: 1: transmit queue 0 timed out 5010 ms
lec:lec_tx_timeout: lec0
lec:lec_start_xmit: lec0:No lecd attached
lec0: NETDEV WATCHDOG: CPU: 1: transmit queue 0 timed out 5010 ms
lec:lec_tx_timeout: lec0
lec:lec_start_xmit: lec0:No lecd attached