============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.2.3764/20525 is trying to acquire lock:
ffff8880761f4fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
ffff8880761f4fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235
but task is already holding lock:
ffff88807afb4fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
ffff88807afb4fb0 (&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
14 locks held by syz.2.3764/20525:
#0: ffff88807df93440 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
#0: ffff88807df93440 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x194/0xa10 mm/mmap.c:1286
#1: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#1: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#1: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:288
#2: ffff888033c82498 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline]
#2: ffff888033c82498 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:402
#3: ffffc90000007ce0 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd4/0x640 kernel/time/timer.c:1745
#4: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#4: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#4: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: hsr_announce+0x89/0x370 net/hsr/hsr_device.c:419
#5: ffff88807afb4fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
#5: ffff88807afb4fb0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330
#6: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#6: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#6: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0xb3/0x2860 net/hsr/hsr_forward.c:738
#7: ffffffff8e75e680 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#7: ffffffff8e75e680 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#7: ffffffff8e75e680 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x28b/0x3870 net/core/dev.c:4772
#8: ffff88807d146228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#7){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:353 [inline]
#8: ffff88807d146228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#7){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline]
#8: ffff88807d146228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#7){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4183 [inline]
#8: ffff88807d146228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#7){+...}-{3:3}, at: __dev_queue_xmit+0x114b/0x3870 net/core/dev.c:4813
#9: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#9: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#9: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: bond_start_xmit+0xb4/0x1900 drivers/net/bonding/bond_main.c:5589
#10: ffffffff8e75e680 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#10: ffffffff8e75e680 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#10: ffffffff8e75e680 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x28b/0x3870 net/core/dev.c:4772
#11: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#11: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#11: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x193/0x1980 net/bridge/br_device.c:52
#12: ffffffff8e75e680 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#12: ffffffff8e75e680 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#12: ffffffff8e75e680 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x28b/0x3870 net/core/dev.c:4772
#13: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#13: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#13: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229
stack backtrace:
CPU: 0 UID: 0 PID: 20525 Comm: syz.2.3764 Not tainted syzkaller #0 PREEMPT(full)
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:5334 [inline]
netdev_start_xmit include/linux/netdevice.h:5343 [inline]
xmit_one net/core/dev.c:3881 [inline]
dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3897
__dev_queue_xmit+0x1557/0x3870 net/core/dev.c:4852
dev_queue_xmit include/linux/netdevice.h:3394 [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:5334 [inline]
netdev_start_xmit include/linux/netdevice.h:5343 [inline]
xmit_one net/core/dev.c:3881 [inline]
dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3897
__dev_queue_xmit+0x1557/0x3870 net/core/dev.c:4852
__bond_start_xmit drivers/net/bonding/bond_main.c:-1 [inline]
bond_start_xmit+0xd5c/0x1900 drivers/net/bonding/bond_main.c:5591
__netdev_start_xmit include/linux/netdevice.h:5334 [inline]
netdev_start_xmit include/linux/netdevice.h:5343 [inline]
xmit_one net/core/dev.c:3881 [inline]
dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3897
sch_direct_xmit+0x251/0x4c0 net/sched/sch_generic.c:372
__dev_xmit_skb net/core/dev.c:4196 [inline]
__dev_queue_xmit+0x1b20/0x3870 net/core/dev.c:4813
dev_queue_xmit include/linux/netdevice.h:3394 [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:ptep_get include/linux/pgtable.h:461 [inline]
RIP: 0010:do_zap_pte_range mm/memory.c:1808 [inline]
RIP: 0010:zap_pte_range mm/memory.c:1929 [inline]
RIP: 0010:zap_pmd_range mm/memory.c:2021 [inline]
RIP: 0010:zap_pud_range mm/memory.c:2049 [inline]
RIP: 0010:zap_p4d_range mm/memory.c:2070 [inline]
RIP: 0010:unmap_page_range+0xd48/0x48f0 mm/memory.c:2091
Code: 1b 48 89 de 48 83 e6 10 31 ff e8 43 7b b1 ff 48 83 e3 10 0f 85 75 28 00 00 48 8b 5c 24 58 48 89 d8 48 c1 e8 03 42 80 3c 28 00 <74> 08 48 89 df e8 de be 1b 00 4c 8b 33 4c 89 74 24 18 4d 29 fc 49
RSP: 0018:ffffc90005e573a0 EFLAGS: 00000246
RAX: 1ffff110082a5a8b RBX: ffff88804152d458 RCX: ffff888038705b80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90005e57670 R08: ffffea00021b23f3 R09: 1ffffd400043647e
R10: dffffc0000000000 R11: fffff9400043647f R12: 00007fa80fe00000
R13: dffffc0000000000 R14: 0000000000000001 R15: 00007fa80fc8b000
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:1175
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: 0033:0x7fa81099c819
Code: Unable to access opcode bytes at 0x7fa81099c7ef.
RSP: 002b:00007fa8118770e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fa810c15fa8 RCX: 00007fa81099c819
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa810c15fa8
RBP: 00007fa810c15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa810c16038 R14: 00007ffecdc59700 R15: 00007ffecdc597e8
ip6_tunnel: ip6gre2 xmit: Local address not yet configured!
----------------
Code disassembly (best guess):
0: 1b 48 89 sbb -0x77(%rax),%ecx
3: de 48 83 fimuls -0x7d(%rax)
6: e6 10 out %al,$0x10
8: 31 ff xor %edi,%edi
a: e8 43 7b b1 ff call 0xffb17b52
f: 48 83 e3 10 and $0x10,%rbx
13: 0f 85 75 28 00 00 jne 0x288e
19: 48 8b 5c 24 58 mov 0x58(%rsp),%rbx
1e: 48 89 d8 mov %rbx,%rax
21: 48 c1 e8 03 shr $0x3,%rax
25: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
* 2a: 74 08 je 0x34 <-- trapping instruction
2c: 48 89 df mov %rbx,%rdi
2f: e8 de be 1b 00 call 0x1bbf12
34: 4c 8b 33 mov (%rbx),%r14
37: 4c 89 74 24 18 mov %r14,0x18(%rsp)
3c: 4d 29 fc sub %r15,%r12
3f: 49 rex.WB