============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz-executor/5848 is trying to acquire lock:
ffff888023d64f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff888023d64f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235
but task is already holding lock:
ffff888064a12f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff888064a12f30 (&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
16 locks held by syz-executor/5848:
#0: ffffffff8dff6910 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1488 [inline]
#0: ffffffff8dff6910 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x131/0x4b0 kernel/fork.c:1541
#1: ffff88807f702220 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:330 [inline]
#1: ffff88807f702220 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x126/0x1b10 mm/mmap.c:1727
#2: ffff88801a05d7e0 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:320 [inline]
#2: ffff88801a05d7e0 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x212/0x1b10 mm/mmap.c:1734
#3: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#3: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#3: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: ___pte_offset_map+0x29/0x250 mm/pgtable-generic.c:286
#4: ffff88802fc0fd98 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
#4: ffff88802fc0fd98 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: __pte_offset_map_lock+0x13e/0x210 mm/pgtable-generic.c:401
#5: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#5: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#5: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: ___pte_offset_map+0x29/0x250 mm/pgtable-generic.c:286
#6: ffff88807942f3d8 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pte_range mm/memory.c:1255 [inline]
#6: ffff88807942f3d8 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pmd_range+0x6d3/0x7f00 mm/memory.c:1390
#7: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#7: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#7: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: page_table_check_set+0x18d/0x730 mm/page_table_check.c:112
#8: ffffc90000007be0 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x5f0 kernel/time/timer.c:1745
#9: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#9: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#9: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: hsr_announce+0x83/0x360 net/hsr/hsr_device.c:419
#10: ffff888064a12f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#10: ffff888064a12f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330
#11: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#11: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#11: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0x9e/0x2860 net/hsr/hsr_forward.c:736
#12: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#12: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#12: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27b/0x3b50 net/core/dev.c:4688
#13: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#13: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#13: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x185/0x1840 net/bridge/br_device.c:52
#14: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#14: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#14: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27b/0x3b50 net/core/dev.c:4688
#15: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#15: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#15: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229
stack backtrace:
CPU: 0 UID: 0 PID: 5848 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_deadlock_bug+0x28b/0x2a0 kernel/locking/lockdep.c:3041
check_deadlock kernel/locking/lockdep.c:3093 [inline]
validate_chain+0x1a3f/0x2140 kernel/locking/lockdep.c:3895
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235
__netdev_start_xmit include/linux/netdevice.h:5248 [inline]
netdev_start_xmit include/linux/netdevice.h:5257 [inline]
xmit_one net/core/dev.c:3845 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3861
__dev_queue_xmit+0x1b8d/0x3b50 net/core/dev.c:4763
dev_queue_xmit include/linux/netdevice.h:3365 [inline]
br_dev_queue_push_xmit+0x6c5/0x890 net/bridge/br_forward.c:53
NF_HOOK+0x320/0x3c0 include/linux/netfilter.h:318
br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66
NF_HOOK+0x320/0x3c0 include/linux/netfilter.h:318
__br_forward+0x41e/0x600 net/bridge/br_forward.c:115
deliver_clone net/bridge/br_forward.c:131 [inline]
maybe_deliver+0xb5/0x160 net/bridge/br_forward.c:191
br_flood+0x31a/0x6a0 net/bridge/br_forward.c:238
br_dev_xmit+0x11b3/0x1840 net/bridge/br_device.c:108
__netdev_start_xmit include/linux/netdevice.h:5248 [inline]
netdev_start_xmit include/linux/netdevice.h:5257 [inline]
xmit_one net/core/dev.c:3845 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3861
__dev_queue_xmit+0x1b8d/0x3b50 net/core/dev.c:4763
dev_queue_xmit include/linux/netdevice.h:3365 [inline]
hsr_xmit net/hsr/hsr_forward.c:438 [inline]
hsr_forward_do net/hsr/hsr_forward.c:579 [inline]
hsr_forward_skb+0x158b/0x2860 net/hsr/hsr_forward.c:741
send_hsr_supervision_frame+0x731/0xcb0 net/hsr/hsr_device.c:364
hsr_announce+0x1d5/0x360 net/hsr/hsr_device.c:421
call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x61a/0x860 kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2404
handle_softirqs+0x286/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 5b 2d d1 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc900041df2a8 EFLAGS: 00000206
RAX: 11fac61498bbe100 RBX: 0000000000000000 RCX: 11fac61498bbe100
RDX: 0000000000000000 RSI: ffffffff8d8f61f0 RDI: ffffffff8bbf0960
RBP: ffffffff8230eced R08: 0000000000000000 R09: ffffffff8230eced
R10: dffffc0000000000 R11: fffff940003084f9 R12: 0000000000000002
R13: ffffffff8df3d6e0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
page_table_check_set+0x1aa/0x730 mm/page_table_check.c:112
page_table_check_ptes_set include/linux/page_table_check.h:76 [inline]
set_ptes include/linux/pgtable.h:292 [inline]
__copy_present_ptes mm/memory.c:1101 [inline]
copy_present_ptes mm/memory.c:1180 [inline]
copy_pte_range mm/memory.c:1303 [inline]
copy_pmd_range+0x4b9b/0x7f00 mm/memory.c:1390
copy_pud_range mm/memory.c:1427 [inline]
copy_p4d_range mm/memory.c:1451 [inline]
copy_page_range+0xc14/0x1270 mm/memory.c:1539
dup_mmap+0xf4c/0x1b10 mm/mmap.c:1834
dup_mm kernel/fork.c:1489 [inline]
copy_mm+0x13c/0x4b0 kernel/fork.c:1541
copy_process+0x1706/0x3c00 kernel/fork.c:2181
kernel_clone+0x21e/0x840 kernel/fork.c:2609
__do_sys_clone kernel/fork.c:2750 [inline]
__se_sys_clone kernel/fork.c:2734 [inline]
__x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2734
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f022b585e93
Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00
RSP: 002b:00007f022b90fca8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f022b585e93
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 0000555578ec77d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 00000000000a9ae1 R15: 00007f022b90fe40
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 00 00 add %al,(%rax)
4: 9c pushf
5: 8f 44 24 30 pop 0x30(%rsp)
9: f7 44 24 30 00 02 00 testl $0x200,0x30(%rsp)
10: 00
11: 0f 85 cd 00 00 00 jne 0xe4
17: f7 44 24 08 00 02 00 testl $0x200,0x8(%rsp)
1e: 00
1f: 74 01 je 0x22
21: fb sti
22: 65 48 8b 05 5b 2d d1 mov %gs:0x10d12d5b(%rip),%rax # 0x10d12d85
29: 10
* 2a: 48 3b 44 24 58 cmp 0x58(%rsp),%rax <-- trapping instruction
2f: 0f 85 f2 00 00 00 jne 0x127
35: 48 83 c4 60 add $0x60,%rsp
39: 5b pop %rbx
3a: 41 5c pop %r12
3c: 41 5d pop %r13
3e: 41 5e pop %r14