============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.3.8508/6739 is trying to acquire lock:
ffff88809a99cf30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff88809a99cf30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235
but task is already holding lock:
ffff888030b58f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff888030b58f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_prp_supervision_frame+0x195/0x6c0 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
16 locks held by syz.3.8508/6739:
#0: ffff888024999eb8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1232
#1: ffff888062f1c420 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3113 [inline]
#1: ffff888062f1c420 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x211/0xb30 fs/read_write.c:682
#2: ffff88804da4c378 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
#2: ffff88804da4c378 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: shmem_file_write_iter+0x7f/0x120 mm/shmem.c:3456
#3: ffff88805d088ca0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:387 [inline]
#3: ffff88805d088ca0 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:369 [inline]
#3: ffff88805d088ca0 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x32/0x300 mm/mmap_lock.c:429
#4: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#4: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#4: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: ___pte_offset_map+0x29/0x250 mm/pgtable-generic.c:286
#5: ffff8880386418b8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
#5: ffff8880386418b8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: __pte_offset_map_lock+0x13e/0x210 mm/pgtable-generic.c:401
#6: ffffc90000007be0 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x5f0 kernel/time/timer.c:1745
#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: hsr_announce+0x83/0x360 net/hsr/hsr_device.c:419
#8: ffff888030b58f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#8: ffff888030b58f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_prp_supervision_frame+0x195/0x6c0 net/hsr/hsr_device.c:390
#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_forward_skb+0x9e/0x2860 net/hsr/hsr_forward.c:736
#10: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#10: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#10: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2ab/0x3180 net/core/dev.c:4742
#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: bond_start_xmit+0xf8/0x1a10 drivers/net/bonding/bond_main.c:5486
#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+0x2ab/0x3180 net/core/dev.c:4742
#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+0x2ab/0x3180 net/core/dev.c:4742
#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: 6739 Comm: syz.3.8508 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:5272 [inline]
netdev_start_xmit include/linux/netdevice.h:5281 [inline]
xmit_one net/core/dev.c:3853 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3869
__dev_queue_xmit+0x14c5/0x3180 net/core/dev.c:4817
dev_queue_xmit include/linux/netdevice.h:3381 [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:5272 [inline]
netdev_start_xmit include/linux/netdevice.h:5281 [inline]
xmit_one net/core/dev.c:3853 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3869
__dev_queue_xmit+0x14c5/0x3180 net/core/dev.c:4817
__bond_start_xmit include/linux/netdevice.h:-1 [inline]
bond_start_xmit+0xdc7/0x1a10 drivers/net/bonding/bond_main.c:5488
__netdev_start_xmit include/linux/netdevice.h:5272 [inline]
netdev_start_xmit include/linux/netdevice.h:5281 [inline]
xmit_one net/core/dev.c:3853 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3869
__dev_queue_xmit+0x14c5/0x3180 net/core/dev.c:4817
dev_queue_xmit include/linux/netdevice.h:3381 [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_prp_supervision_frame+0x35b/0x6c0 net/hsr/hsr_device.c:405
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:__sanitizer_cov_trace_const_cmp4+0x0/0x90 kernel/kcov.c:313
Code: 7c 11 10 48 89 74 11 18 48 89 44 11 20 e9 c8 4c 8b 09 cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 14 25 08 f0 6e 92 65 8b 0d 28 e8
RSP: 0018:ffffc9000c1a7600 EFLAGS: 00000246
RAX: ffffffff8230e8af RBX: 000000001272e201 RCX: ffff888029b99e40
RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffff88805d089387 R09: 1ffff1100ba11270
R10: dffffc0000000000 R11: ffffed100ba11271 R12: 000000001272e201
R13: 000000001272e225 R14: ffff888034ebdaf8 R15: ffff88805d088a00
__page_table_check_ptes_set+0x96/0x2f0 mm/page_table_check.c:-1
page_table_check_ptes_set include/linux/page_table_check.h:76 [inline]
set_ptes+0x231/0x240 include/linux/pgtable.h:292
do_anonymous_page mm/memory.c:5234 [inline]
do_pte_missing mm/memory.c:4360 [inline]
handle_pte_fault mm/memory.c:6195 [inline]
__handle_mm_fault+0x3a23/0x5400 mm/memory.c:6336
handle_mm_fault+0x40a/0x8e0 mm/memory.c:6505
do_user_addr_fault+0x764/0x1380 arch/x86/mm/fault.c:1387
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:fault_in_readable+0x8e/0x130 mm/gup.c:2161
Code: a9 00 00 00 0f 01 cb 0f ae e8 4d 85 f6 40 0f 95 c5 4c 89 ff 4c 89 f6 e8 e0 8f b6 ff 4d 39 f7 0f 97 c0 40 84 c5 74 43 4d 89 f5 <41> 8a 45 00 88 44 24 07 49 81 e5 00 f0 ff ff 4d 8d a5 00 10 00 00
RSP: 0018:ffffc9000c1a7aa8 EFLAGS: 00050202
RAX: ffffffff82097601 RBX: 0000000000001000 RCX: ffff888029b99e40
RDX: 0000000000000002 RSI: 000020000015f000 RDI: 0000200000160000
RBP: dffffc0000000001 R08: ffff888029b99e40 R09: 0000000000000002
R10: 0000000000000001 R11: 0000000000000002 R12: 00007ffffffff000
R13: 000020000015f000 R14: 000020000015f000 R15: 0000200000160000
fault_in_iov_iter_readable+0x1b4/0x2f0 lib/iov_iter.c:94
generic_perform_write+0x7b5/0x900 mm/filemap.c:4304
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3466
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
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: 0033:0x7fe76698f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe767808038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe766be5fa0 RCX: 00007fe76698f749
RDX: 00000000ffffff6a RSI: 0000200000000000 RDI: 0000000000000009
RBP: 00007fe766a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe766be6038 R14: 00007fe766be5fa0 R15: 00007ffddd2dfc78
----------------
Code disassembly (best guess):
0: 7c 11 jl 0x13
2: 10 48 89 adc %cl,-0x77(%rax)
5: 74 11 je 0x18
7: 18 48 89 sbb %cl,-0x77(%rax)
a: 44 11 20 adc %r12d,(%rax)
d: e9 c8 4c 8b 09 jmp 0x98b4cda
12: cc int3
13: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
1a: 90 nop
1b: 90 nop
1c: 90 nop
1d: 90 nop
1e: 90 nop
1f: 90 nop
20: 90 nop
21: 90 nop
22: 90 nop
23: 90 nop
24: 90 nop
25: 90 nop
26: 90 nop
27: 90 nop
28: 90 nop
29: 90 nop
* 2a: f3 0f 1e fa endbr64 <-- trapping instruction
2e: 48 8b 04 24 mov (%rsp),%rax
32: 65 48 8b 14 25 08 f0 mov %gs:0xffffffff926ef008,%rdx
39: 6e 92
3b: 65 gs
3c: 8b .byte 0x8b
3d: 0d .byte 0xd
3e: 28 e8 sub %ch,%al