============================================
WARNING: possible recursive locking detected
syzkaller #0 Tainted: G L
--------------------------------------------
syz.4.356/7567 is trying to acquire lock:
ffff888074ccef70 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
ffff888074ccef70 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x208/0x400 net/hsr/hsr_device.c:235
but task is already holding lock:
ffff88807a6a4f70 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
ffff88807a6a4f70 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_prp_supervision_frame+0x17c/0x5e0 net/hsr/hsr_device.c:390
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.4.356/7567:
#0: ffff888076ae31b8 (&u->iolock){+.+.}-{4:4}, at: __unix_dgram_recvmsg+0x255/0xc30 net/unix/af_unix.c:2568
#1: ffffc90000007ca8 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0x11f/0x670 kernel/time/timer.c:1745
#2: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#2: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#2: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: hsr_announce+0x88/0x3e0 net/hsr/hsr_device.c:419
#3: ffff88807a6a4f70 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
#3: ffff88807a6a4f70 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_prp_supervision_frame+0x17c/0x5e0 net/hsr/hsr_device.c:390
#4: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#4: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#4: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0xa7/0x28a0 net/hsr/hsr_forward.c:738
#5: ffffffff8e7e9380 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#5: ffffffff8e7e9380 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#5: ffffffff8e7e9380 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x274/0x4750 net/core/dev.c:4754
#6: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#6: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#6: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: bond_start_xmit+0xb7/0x10d0 drivers/net/bonding/bond_main.c:5527
#7: ffffffff8e7e9380 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#7: ffffffff8e7e9380 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#7: ffffffff8e7e9380 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x274/0x4750 net/core/dev.c:4754
#8: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#8: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#8: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x181/0x1880 net/bridge/br_device.c:52
#9: ffffffff8e7e9380 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#9: ffffffff8e7e9380 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#9: ffffffff8e7e9380 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x274/0x4750 net/core/dev.c:4754
#10: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#10: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#10: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x39/0x400 net/hsr/hsr_device.c:229
stack backtrace:
CPU: 0 UID: 0 PID: 7567 Comm: syz.4.356 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_deadlock_bug.cold+0xbd/0xca kernel/locking/lockdep.c:3041
check_deadlock kernel/locking/lockdep.c:3093 [inline]
validate_chain kernel/locking/lockdep.c:3895 [inline]
__lock_acquire+0x12bb/0x2630 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline]
_raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:347 [inline]
hsr_dev_xmit+0x208/0x400 net/hsr/hsr_device.c:235
__netdev_start_xmit include/linux/netdevice.h:5275 [inline]
netdev_start_xmit include/linux/netdevice.h:5284 [inline]
xmit_one net/core/dev.c:3864 [inline]
dev_hard_start_xmit+0x121/0x7d0 net/core/dev.c:3880
__dev_queue_xmit+0x6dd/0x4750 net/core/dev.c:4829
dev_queue_xmit include/linux/netdevice.h:3384 [inline]
br_dev_queue_push_xmit+0x360/0x550 net/bridge/br_forward.c:53
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
br_forward_finish+0x102/0x4d0 net/bridge/br_forward.c:66
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
__br_forward+0x6b1/0x970 net/bridge/br_forward.c:115
deliver_clone net/bridge/br_forward.c:131 [inline]
maybe_deliver+0xf0/0x180 net/bridge/br_forward.c:191
br_flood+0x193/0x650 net/bridge/br_forward.c:238
br_dev_xmit+0x10b0/0x1880 net/bridge/br_device.c:108
__netdev_start_xmit include/linux/netdevice.h:5275 [inline]
netdev_start_xmit include/linux/netdevice.h:5284 [inline]
xmit_one net/core/dev.c:3864 [inline]
dev_hard_start_xmit+0x121/0x7d0 net/core/dev.c:3880
__dev_queue_xmit+0x6dd/0x4750 net/core/dev.c:4829
dev_queue_xmit include/linux/netdevice.h:3384 [inline]
bond_dev_queue_xmit+0xc9/0x180 drivers/net/bonding/bond_main.c:311
bond_3ad_xor_xmit drivers/net/bonding/bond_main.c:5234 [inline]
__bond_start_xmit drivers/net/bonding/bond_main.c:5501 [inline]
bond_start_xmit+0x2f6/0x10d0 drivers/net/bonding/bond_main.c:5529
__netdev_start_xmit include/linux/netdevice.h:5275 [inline]
netdev_start_xmit include/linux/netdevice.h:5284 [inline]
xmit_one net/core/dev.c:3864 [inline]
dev_hard_start_xmit+0x121/0x7d0 net/core/dev.c:3880
__dev_queue_xmit+0x6dd/0x4750 net/core/dev.c:4829
dev_queue_xmit include/linux/netdevice.h:3384 [inline]
hsr_xmit net/hsr/hsr_forward.c:440 [inline]
hsr_forward_do net/hsr/hsr_forward.c:581 [inline]
hsr_forward_skb+0xcbc/0x28a0 net/hsr/hsr_forward.c:743
send_prp_supervision_frame+0x3e6/0x5e0 net/hsr/hsr_device.c:405
hsr_announce+0x169/0x3e0 net/hsr/hsr_device.c:421
call_timer_fn+0x19a/0x670 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers+0x757/0xb30 kernel/time/timer.c:2373
__run_timer_base kernel/time/timer.c:2385 [inline]
__run_timer_base kernel/time/timer.c:2377 [inline]
run_timer_base+0x114/0x190 kernel/time/timer.c:2394
run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2404
handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xef/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 16 83 52 f6 48 89 df e8 fe d2 52 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 95 09 43 f6 65 8b 05 9e 1e 7b 08 85 c0 74 16 5b
RSP: 0018:ffffc9000655f838 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffff888076ae3300 RCX: 0000000000000040
RDX: 0000000000000000 RSI: ffffffff8de713c7 RDI: ffffffff8c1aefa0
RBP: 0000000000000286 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffff888076ae3150
R13: ffff888076ae3340 R14: ffff888076ae2ca8 R15: ffff888074edc780
__unix_dgram_recvmsg+0x31a/0xc30 net/unix/af_unix.c:2596
unix_dgram_recvmsg+0xd0/0x110 net/unix/af_unix.c:2670
sock_recvmsg_nosec net/socket.c:1078 [inline]
____sys_recvmsg+0x5f7/0x6b0 net/socket.c:2810
___sys_recvmsg+0x16a/0x1a0 net/socket.c:2854
do_recvmmsg+0x301/0x760 net/socket.c:2949
__sys_recvmmsg net/socket.c:3023 [inline]
__do_sys_recvmmsg net/socket.c:3046 [inline]
__se_sys_recvmmsg net/socket.c:3039 [inline]
__x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3039
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f833979c629
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:00007f833a64d028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f8339a16090 RCX: 00007f833979c629
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007f8339832b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8339a16128 R14: 00007f8339a16090 R15: 00007ffda118df58
----------------
Code disassembly (best guess):
0: f5 cmc
1: 53 push %rbx
2: 48 8b 74 24 10 mov 0x10(%rsp),%rsi
7: 48 89 fb mov %rdi,%rbx
a: 48 83 c7 18 add $0x18,%rdi
e: e8 16 83 52 f6 call 0xf6528329
13: 48 89 df mov %rbx,%rdi
16: e8 fe d2 52 f6 call 0xf652d319
1b: f7 c5 00 02 00 00 test $0x200,%ebp
21: 75 23 jne 0x46
23: 9c pushf
24: 58 pop %rax
25: f6 c4 02 test $0x2,%ah
28: 75 37 jne 0x61
* 2a: bf 01 00 00 00 mov $0x1,%edi <-- trapping instruction
2f: e8 95 09 43 f6 call 0xf64309c9
34: 65 8b 05 9e 1e 7b 08 mov %gs:0x87b1e9e(%rip),%eax # 0x87b1ed9
3b: 85 c0 test %eax,%eax
3d: 74 16 je 0x55
3f: 5b pop %rbx