============================================
WARNING: possible recursive locking detected
syzkaller #0 Tainted: G L
--------------------------------------------
syz.6.7735/2883 is trying to acquire lock:
ffff88804a658fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
ffff88804a658fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235
but task is already holding lock:
ffff888064738fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
ffff888064738fb0 (&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 syz.6.7735/2883:
#0: ffff8880323e4cc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:611 [inline]
#0: ffff8880323e4cc0 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline]
#0: ffff8880323e4cc0 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:501
#1: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#1: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#1: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
#1: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xa5/0x23c0 arch/x86/kernel/unwind_orc.c:495
#2: ffffc90000a08ce0 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd4/0x640 kernel/time/timer.c:1745
#3: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#3: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#3: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: hsr_announce+0x89/0x370 net/hsr/hsr_device.c:419
#4: ffff888064738fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
#4: ffff888064738fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330
#5: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#5: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#5: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0xb3/0x2860 net/hsr/hsr_forward.c:738
#6: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#6: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#6: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x277/0x3890 net/core/dev.c:4778
#7: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#7: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#7: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x193/0x1980 net/bridge/br_device.c:52
#8: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#8: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#8: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x277/0x3890 net/core/dev.c:4778
#9: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#9: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#9: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229
stack backtrace:
CPU: 1 UID: 0 PID: 2883 Comm: syz.6.7735 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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:5325 [inline]
netdev_start_xmit include/linux/netdevice.h:5334 [inline]
xmit_one net/core/dev.c:3888 [inline]
dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3904
__dev_queue_xmit+0x16d1/0x3890 net/core/dev.c:4854
dev_queue_xmit include/linux/netdevice.h:3385 [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
deliver_clone net/bridge/br_forward.c:131 [inline]
maybe_deliver net/bridge/br_forward.c:191 [inline]
br_flood+0x6ee/0xb80 net/bridge/br_forward.c:238
br_dev_xmit+0x12bd/0x1980 net/bridge/br_device.c:108
__netdev_start_xmit include/linux/netdevice.h:5325 [inline]
netdev_start_xmit include/linux/netdevice.h:5334 [inline]
xmit_one net/core/dev.c:3888 [inline]
dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3904
__dev_queue_xmit+0x16d1/0x3890 net/core/dev.c:4854
dev_queue_xmit include/linux/netdevice.h:3385 [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:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872
Code: e9 30 ff ff ff e8 65 39 0e 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 e1 26 7b 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 46 1f 11 0a cc 48 8d 3d 8e 93 73
RSP: 0018:ffffc9000e4cea98 EFLAGS: 00000282
RAX: 58b4b2e3fa148600 RBX: 0000000000000246 RCX: 0000000000000046
RDX: 00000000b5c0162b RSI: ffffffff8e16c412 RDI: ffffffff8c27d580
RBP: 0000000000000000 R08: ffffffff81768a55 R09: ffffffff8e75e5a0
R10: ffffc9000e4cebf8 R11: ffffffff81b0dc10 R12: 0000000000000002
R13: ffffffff8e75e5a0 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
save_stack+0x122/0x230 mm/page_owner.c:165
__set_page_owner+0x8d/0x4c0 mm/page_owner.c:341
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
prep_new_page mm/page_alloc.c:1897 [inline]
get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2490
folio_alloc_mpol_noprof mm/mempolicy.c:2509 [inline]
vma_alloc_folio_noprof+0xea/0x210 mm/mempolicy.c:2544
folio_prealloc mm/memory.c:-1 [inline]
wp_page_copy mm/memory.c:3780 [inline]
do_wp_page+0x1204/0x5a00 mm/memory.c:4241
handle_pte_fault mm/memory.c:6333 [inline]
__handle_mm_fault mm/memory.c:6455 [inline]
handle_mm_fault+0x1520/0x3310 mm/memory.c:6624
do_user_addr_fault+0x75b/0x1340 arch/x86/mm/fault.c:1385
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:__put_user_nocheck_4+0x3/0x10 arch/x86/lib/putuser.S:104
Code: d9 0f 01 cb 89 01 31 c9 0f 01 ca c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 01 cb <89> 01 31 c9 0f 01 ca e9 51 75 03 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000e4cf8b8 EFLAGS: 00050202
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000020000033d030
RDX: ffff888040983d00 RSI: 0000000000000002 RDI: 00000000ffffffff
RBP: ffffc9000e4cfa30 R08: ffffc9000e4cf687 R09: 1ffff92001c99ed0
R10: dffffc0000000000 R11: fffff52001c99ed1 R12: 1ffff92001c99f24
R13: 0000000000000002 R14: 000020000033d000 R15: dffffc0000000000
____sys_recvmsg+0x2be/0x4a0 net/socket.c:2825
___sys_recvmsg+0x215/0x590 net/socket.c:2854
do_recvmmsg+0x334/0x800 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+0x198/0x250 net/socket.c:3039
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc1cdf9c819
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:00007fc1cee57028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fc1ce216090 RCX: 00007fc1cdf9c819
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007fc1ce032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc1ce216128 R14: 00007fc1ce216090 R15: 00007fc1ce33fa48
----------------
Code disassembly (best guess):
0: e9 30 ff ff ff jmp 0xffffff35
5: e8 65 39 0e 0a call 0xa0e396f
a: f7 c3 00 02 00 00 test $0x200,%ebx
10: 0f 84 38 ff ff ff je 0xffffff4e
16: 65 48 8b 05 e1 26 7b mov %gs:0x117b26e1(%rip),%rax # 0x117b26ff
1d: 11
1e: 48 3b 44 24 30 cmp 0x30(%rsp),%rax
23: 75 33 jne 0x58
25: fb sti
26: 48 83 c4 38 add $0x38,%rsp
* 2a: 5b pop %rbx <-- trapping instruction
2b: 41 5c pop %r12
2d: 41 5d pop %r13
2f: 41 5e pop %r14
31: 41 5f pop %r15
33: 5d pop %rbp
34: e9 46 1f 11 0a jmp 0xa111f7f
39: cc int3
3a: 48 rex.W
3b: 8d .byte 0x8d
3c: 3d .byte 0x3d
3d: 8e .byte 0x8e
3e: 93 xchg %eax,%ebx
3f: 73 .byte 0x73