============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
modprobe/5600 is trying to acquire lock:
ffff8880476aaf30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff8880476aaf30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235
but task is already holding lock:
ffff8880777e8f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff8880777e8f30 (&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
10 locks held by modprobe/5600:
#0: ffff888079969760 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:330 [inline]
#0: ffff888079969760 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x211/0x4d0 mm/util.c:579
#1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
#1: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xa5/0x2390 arch/x86/kernel/unwind_orc.c:479
#2: ffffc90000007be0 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x5f0 kernel/time/timer.c:1744
#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: hsr_announce+0x83/0x360 net/hsr/hsr_device.c:419
#4: ffff8880777e8f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#4: ffff8880777e8f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330
#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: hsr_forward_skb+0x9e/0x2860 net/hsr/hsr_forward.c:736
#6: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#6: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#6: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x284/0x3740 net/core/dev.c:4736
#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: br_dev_xmit+0x185/0x1840 net/bridge/br_device.c:52
#8: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#8: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#8: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x284/0x3740 net/core/dev.c:4736
#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_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229
stack backtrace:
CPU: 0 UID: 0 PID: 5600 Comm: modprobe 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:5259 [inline]
netdev_start_xmit include/linux/netdevice.h:5268 [inline]
xmit_one net/core/dev.c:3853 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3869
__dev_queue_xmit+0x172a/0x3740 net/core/dev.c:4811
dev_queue_xmit include/linux/netdevice.h:3368 [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
br_dev_xmit+0x11b3/0x1840 net/bridge/br_device.c:108
__netdev_start_xmit include/linux/netdevice.h:5259 [inline]
netdev_start_xmit include/linux/netdevice.h:5268 [inline]
xmit_one net/core/dev.c:3853 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3869
__dev_queue_xmit+0x172a/0x3740 net/core/dev.c:4811
dev_queue_xmit include/linux/netdevice.h:3368 [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:1747
expire_timers kernel/time/timer.c:1798 [inline]
__run_timers kernel/time/timer.c:2372 [inline]
__run_timer_base+0x61a/0x860 kernel/time/timer.c:2384
run_timer_base kernel/time/timer.c:2393 [inline]
run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
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:deref_stack_reg arch/x86/kernel/unwind_orc.c:406 [inline]
RIP: 0010:unwind_next_frame+0xc4e/0x2390 arch/x86/kernel/unwind_orc.c:585
Code: 4c 39 e0 0f 96 c0 20 c8 3c 01 0f 85 df 0c 00 00 48 89 df e8 84 23 00 00 48 89 c3 48 bd 00 00 00 00 00 fc ff df 48 8b 44 24 30 <80> 3c 28 00 4c 8b 7c 24 18 74 08 4c 89 ff e8 3f 2e b2 00 49 89 1f
RSP: 0018:ffffc90003f7f238 EFLAGS: 00000202
RAX: 1ffff920007efe6a RBX: ffffffff820f986f RCX: 1ffff920007efe01
RDX: ffffffff9015ddd4 RSI: 0000000000000002 RDI: ffffc90003f7fe78
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff81738c45
R10: ffffc90003f7f358 R11: ffffffff81ac2e10 R12: ffffc90003f80000
R13: 1ffff920007efe63 R14: ffffc90003f7f308 R15: ffffc90003f78000
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:342 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4978 [inline]
slab_alloc_node mm/slub.c:5288 [inline]
kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5295
vm_area_alloc+0x24/0x140 mm/vma_init.c:32
__mmap_new_vma mm/vma.c:2461 [inline]
__mmap_region mm/vma.c:2670 [inline]
mmap_region+0xdcd/0x2110 mm/vma.c:2740
do_mmap+0xc45/0x10d0 mm/mmap.c:558
vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:581
ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:604
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: 0033:0x7ff049cee242
Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00
RSP: 002b:00007ffcc1980208 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007ff049a04000 RCX: 00007ff049cee242
RDX: 0000000000000003 RSI: 0000000000002000 RDI: 00007ff049a04000
RBP: 0000000000000812 R08: 0000000000000000 R09: 000000000000d000
R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffcc19802c8
R13: 00007ff049cc3580 R14: 00007ffcc1980680 R15: 00000fff98330044
----------------
Code disassembly (best guess):
0: 4c 39 e0 cmp %r12,%rax
3: 0f 96 c0 setbe %al
6: 20 c8 and %cl,%al
8: 3c 01 cmp $0x1,%al
a: 0f 85 df 0c 00 00 jne 0xcef
10: 48 89 df mov %rbx,%rdi
13: e8 84 23 00 00 call 0x239c
18: 48 89 c3 mov %rax,%rbx
1b: 48 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%rbp
22: fc ff df
25: 48 8b 44 24 30 mov 0x30(%rsp),%rax
* 2a: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) <-- trapping instruction
2e: 4c 8b 7c 24 18 mov 0x18(%rsp),%r15
33: 74 08 je 0x3d
35: 4c 89 ff mov %r15,%rdi
38: e8 3f 2e b2 00 call 0xb22e7c
3d: 49 89 1f mov %rbx,(%r15)