[syzbot] [net?] BUG: spinlock already unlocked in lec_atm_close

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1f5ffc672165 Fix mismerge of the arm64 / timer-core interr..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12b85906580000
kernel config: https://syzkaller.appspot.com/x/.config?x=95729ed00549063a
dashboard link: https://syzkaller.appspot.com/bug?extid=49a9c7b281bb147f8eb3
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6b552538b97f/disk-1f5ffc67.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/724a3a1d69d7/vmlinux-1f5ffc67.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ea684969e2c2/bzImage-1f5ffc67.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+49a9c7...@syzkaller.appspotmail.com

BUG: spinlock already unlocked on CPU#0, syz.2.25/6044
lock: 0xffff888032ea0ea0, .magic: dead4ead, .owner: <none>/-1, .owner_cpu: -1
CPU: 0 UID: 0 PID: 6044 Comm: syz.2.25 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
spin_bug kernel/locking/spinlock_debug.c:78 [inline]
debug_spin_unlock kernel/locking/spinlock_debug.c:101 [inline]
do_raw_spin_unlock+0x143/0x210 kernel/locking/spinlock_debug.c:141
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:177 [inline]
_raw_spin_unlock_irqrestore+0x23/0x80 kernel/locking/spinlock.c:198
spin_unlock_irqrestore include/linux/spinlock.h:408 [inline]
lec_arp_destroy net/atm/lec.c:1543 [inline]
lec_atm_close+0x976/0x9e0 net/atm/lec.c:497
vcc_destroy_socket net/atm/common.c:181 [inline]
vcc_release+0x10f/0x580 net/atm/common.c:205
svc_release+0x6c/0xd0 net/atm/svc.c:95
__sock_release net/socket.c:722 [inline]
sock_close+0xc3/0x240 net/socket.c:1514
__fput+0x44f/0xa60 fs/file_table.c:510
task_work_run+0x1d9/0x270 kernel/task_work.c:233
get_signal+0x11eb/0x1330 kernel/signal.c:2811
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:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1af9f9c819
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:00007f1afae30028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f1afa215fa0 RCX: 00007f1af9f9c819
RDX: 0000000000000000 RSI: 00000000000061d0 RDI: 0000000000000005
RBP: 00007f1afa032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1afa216038 R14: 00007f1afa215fa0 R15: 00007ffdc6f7add8
</TASK>
------------[ cut here ]------------
pvqspinlock: lock 0xffff888032ea0ea0 has corrupted value 0x0!
WARNING: kernel/locking/qspinlock_paravirt.h:506 at __pv_queued_spin_unlock_slowpath+0x1a5/0x270 kernel/locking/qspinlock_paravirt.h:504, CPU#0: syz.2.25/6044
Modules linked in:
CPU: 0 UID: 0 PID: 6044 Comm: syz.2.25 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:__pv_queued_spin_unlock_slowpath+0x1ce/0x270 kernel/locking/qspinlock_paravirt.h:504
Code: 04 48 89 df be 04 00 00 00 e8 4e 58 7b f6 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 87 00 00 00 8b 13 4c 89 f7 48 89 de <67> 48 0f b9 3a eb 98 48 c7 c7 30 c8 82 8e 4c 89 f6 4c 89 fa e8 f9
RSP: 0018:ffffc90005087920 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff888032ea0ea0 RCX: ffffffff8bb5d542
RDX: 0000000000000000 RSI: ffff888032ea0ea0 RDI: ffffffff90357220
RBP: 1ffff110065d41d5 R08: ffff888032ea0ea3 R09: 1ffff110065d41d4
R10: dffffc0000000000 R11: ffffed10065d41d5 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff90357220 R15: ffff888032ea0ea8
FS: 00007f1afae306c0(0000) GS:ffff888125245000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1994be92f8 CR3: 000000007abce000 CR4: 00000000003526f0
Call Trace:
<TASK>
__raw_callee_save___pv_queued_spin_unlock_slowpath+0x15/0x30
.slowpath+0x9/0x18
pv_queued_spin_unlock arch/x86/include/asm/paravirt-spinlock.h:40 [inline]
queued_spin_unlock arch/x86/include/asm/paravirt-spinlock.h:72 [inline]
do_raw_spin_unlock+0xf5/0x210 kernel/locking/spinlock_debug.c:142
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:177 [inline]
_raw_spin_unlock_irqrestore+0x23/0x80 kernel/locking/spinlock.c:198
spin_unlock_irqrestore include/linux/spinlock.h:408 [inline]
lec_arp_destroy net/atm/lec.c:1543 [inline]
lec_atm_close+0x976/0x9e0 net/atm/lec.c:497
vcc_destroy_socket net/atm/common.c:181 [inline]
vcc_release+0x10f/0x580 net/atm/common.c:205
svc_release+0x6c/0xd0 net/atm/svc.c:95
__sock_release net/socket.c:722 [inline]
sock_close+0xc3/0x240 net/socket.c:1514
__fput+0x44f/0xa60 fs/file_table.c:510
task_work_run+0x1d9/0x270 kernel/task_work.c:233
get_signal+0x11eb/0x1330 kernel/signal.c:2811
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:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1af9f9c819
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:00007f1afae30028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f1afa215fa0 RCX: 00007f1af9f9c819
RDX: 0000000000000000 RSI: 00000000000061d0 RDI: 0000000000000005
RBP: 00007f1afa032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1afa216038 R14: 00007f1afa215fa0 R15: 00007ffdc6f7add8
</TASK>
----------------
Code disassembly (best guess):
0: 04 48 add $0x48,%al
2: 89 df mov %ebx,%edi
4: be 04 00 00 00 mov $0x4,%esi
9: e8 4e 58 7b f6 call 0xf67b585c
e: 48 89 d8 mov %rbx,%rax
11: 48 c1 e8 03 shr $0x3,%rax
15: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax
1a: 84 c0 test %al,%al
1c: 0f 85 87 00 00 00 jne 0xa9
22: 8b 13 mov (%rbx),%edx
24: 4c 89 f7 mov %r14,%rdi
27: 48 89 de mov %rbx,%rsi
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: eb 98 jmp 0xffffffc9
31: 48 c7 c7 30 c8 82 8e mov $0xffffffff8e82c830,%rdi
38: 4c 89 f6 mov %r14,%rsi
3b: 4c 89 fa mov %r15,%rdx
3e: e8 .byte 0xe8
3f: f9 stc


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