============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.2.3937/21821 is trying to acquire lock:
ffff88806a908f70 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
ffff88806a908f70 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235
but task is already holding lock:
ffff88803546cf70 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
ffff88803546cf70 (&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
12 locks held by syz.2.3937/21821:
#0: ffff888054e81bc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
#0: ffff888054e81bc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x194/0xa10 mm/mmap.c:1286
#1: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#1: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#1: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:288
#2: ffff8880795f4978 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline]
#2: ffff8880795f4978 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:402
#3: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#3: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#3: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: page_table_check_clear+0x144/0x5f0 mm/page_table_check.c:77
#4: ffffc90000007ce0 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd4/0x640 kernel/time/timer.c:1745
#5: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#5: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#5: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: hsr_announce+0x89/0x370 net/hsr/hsr_device.c:419
#6: ffff88803546cf70 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
#6: ffff88803546cf70 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330
#7: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#7: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#7: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0xb3/0x2860 net/hsr/hsr_forward.c:738
#8: ffffffff8e75e480 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#8: ffffffff8e75e480 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#8: ffffffff8e75e480 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x28b/0x3870 net/core/dev.c:4763
#9: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#9: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#9: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x193/0x1980 net/bridge/br_device.c:52
#10: ffffffff8e75e480 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#10: ffffffff8e75e480 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#10: ffffffff8e75e480 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x28b/0x3870 net/core/dev.c:4763
#11: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#11: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#11: ffffffff8e75e420 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229
stack backtrace:
CPU: 0 UID: 0 PID: 21821 Comm: syz.2.3937 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
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+0xf0/0x2e0 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:178
spin_lock_bh include/linux/spinlock.h:347 [inline]
hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235
__netdev_start_xmit include/linux/netdevice.h:5324 [inline]
netdev_start_xmit include/linux/netdevice.h:5333 [inline]
xmit_one net/core/dev.c:3872 [inline]
dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3888
__dev_queue_xmit+0x1557/0x3870 net/core/dev.c:4843
dev_queue_xmit include/linux/netdevice.h:3384 [inline]
br_dev_queue_push_xmit+0x370/0x4a0 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
br_dev_xmit+0x12bd/0x1980 net/bridge/br_device.c:108
__netdev_start_xmit include/linux/netdevice.h:5324 [inline]
netdev_start_xmit include/linux/netdevice.h:5333 [inline]
xmit_one net/core/dev.c:3872 [inline]
dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3888
__dev_queue_xmit+0x1557/0x3870 net/core/dev.c:4843
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+0x157b/0x2860 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+0x192/0x640 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
handle_softirqs+0x22a/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x5f/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+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__sanitizer_cov_trace_pc+0x5c/0x70 kernel/kcov.c:235
Code: 70 16 00 00 83 fa 02 75 21 48 8b 91 78 16 00 00 48 8b 32 48 8d 7e 01 8b 89 74 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 8f 1a ec 09 cc 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90
RSP: 0018:ffffc90004027310 EFLAGS: 00000293
RAX: ffffffff823c0536 RBX: 000000000003ccc5 RCX: ffff88803173bd00
RDX: 0000000000000000 RSI: ffffffff8c27b4e0 RDI: 000000000003ccc5
RBP: 0000000000000001 R08: ffffffff823c1524 R09: ffffffff8e75e420
R10: dffffc0000000000 R11: fffff940001e6629 R12: 000000000003ccc5
R13: 000000000003ccc5 R14: ffffea0000f33148 R15: ffffea0000f33158
page_ext_lookup+0x16/0x180 mm/page_ext.c:512
page_ext_iter_begin include/linux/page_ext.h:133 [inline]
page_table_check_clear+0x238/0x5f0 mm/page_table_check.c:78
ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline]
get_and_clear_full_ptes include/linux/pgtable.h:846 [inline]
zap_present_folio_ptes mm/memory.c:1643 [inline]
zap_present_ptes mm/memory.c:1725 [inline]
do_zap_pte_range mm/memory.c:1827 [inline]
zap_pte_range mm/memory.c:1929 [inline]
zap_pmd_range mm/memory.c:2021 [inline]
zap_pud_range mm/memory.c:2049 [inline]
zap_p4d_range mm/memory.c:2070 [inline]
unmap_page_range+0x33b3/0x48f0 mm/memory.c:2091
unmap_single_vma mm/memory.c:2133 [inline]
unmap_vmas+0x48f/0x6a0 mm/memory.c:2171
exit_mmap+0x280/0xa10 mm/mmap.c:1302
__mmput+0x118/0x430 kernel/fork.c:1174
exit_mm+0x168/0x220 kernel/exit.c:581
do_exit+0x6a2/0x23c0 kernel/exit.c:964
do_group_exit+0x21b/0x2d0 kernel/exit.c:1118
get_signal+0x1284/0x1330 kernel/signal.c:3034
arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa6a239c799
Code: Unable to access opcode bytes at 0x7fa6a239c76f.
RSP: 002b:00007fa6a31de0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007fa6a2615fa8 RCX: 00007fa6a239c799
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fa6a2615fac
RBP: 00007fa6a2615fa0 R08: 3fffffffffffffff R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa6a2616038 R14: 00007ffc67758500 R15: 00007ffc677585e8
----------------
Code disassembly (best guess):
0: 70 16 jo 0x18
2: 00 00 add %al,(%rax)
4: 83 fa 02 cmp $0x2,%edx
7: 75 21 jne 0x2a
9: 48 8b 91 78 16 00 00 mov 0x1678(%rcx),%rdx
10: 48 8b 32 mov (%rdx),%rsi
13: 48 8d 7e 01 lea 0x1(%rsi),%rdi
17: 8b 89 74 16 00 00 mov 0x1674(%rcx),%ecx
1d: 48 39 cf cmp %rcx,%rdi
20: 73 08 jae 0x2a
22: 48 89 3a mov %rdi,(%rdx)
25: 48 89 44 f2 08 mov %rax,0x8(%rdx,%rsi,8)
* 2a: e9 8f 1a ec 09 jmp 0x9ec1abe <-- trapping instruction
2f: cc int3
30: 66 66 66 66 66 2e 0f data16 data16 data16 data16 cs nopw 0x0(%rax,%rax,1)
37: 1f 84 00 00 00 00 00
3e: 90 nop
3f: 90 nop