From: syzbot <syzbot+5d2b94b77112148d1744@syzkaller.appspotmail.com>
To: bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
mingo@redhat.com, pbonzini@redhat.com, seanjc@google.com,
syzkaller-bugs@googlegroups.com, tglx@kernel.org,
x86@kernel.org
Subject: [syzbot] [kvm-x86?] WARNING in hv_tlb_flush_enqueue
Date: Mon, 22 Jun 2026 10:01:26 -0700 [thread overview]
Message-ID: <6a396a66.52ae72c2.136ac7.0002.GAE@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: 8cd8cf7a07e5 Merge tag 'scsi-misc' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1012a7a1580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e69294ccc24d9da
dashboard link: https://syzkaller.appspot.com/bug?extid=5d2b94b77112148d1744
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14c0db7a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13dd001c580000
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-8cd8cf7a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b15ef084e059/vmlinux-8cd8cf7a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a22f25c3f8ee/bzImage-8cd8cf7a.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5d2b94b77112148d1744@syzkaller.appspotmail.com
------------[ cut here ]------------
pvqspinlock: lock 0xffff88802c0c8790 has corrupted value 0x0!
WARNING: kernel/locking/qspinlock_paravirt.h:504 at __pv_queued_spin_unlock_slowpath+0x220/0x2e0 kernel/locking/qspinlock_paravirt.h:504, CPU#0: syz.0.3154/18851
Modules linked in:
CPU: 0 UID: 0 PID: 18851 Comm: syz.0.3154 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__pv_queued_spin_unlock_slowpath+0x223/0x2e0 kernel/locking/qspinlock_paravirt.h:504
Code: fc ff df 48 c1 ea 03 0f b6 14 02 4c 89 e0 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 4d 41 8b 14 24 48 8d 3d 40 00 44 05 4c 89 e6 <67> 48 0f b9 3a e9 2f ff ff ff 48 89 df 48 89 14 24 e8 17 07 e0 f6
RSP: 0018:ffffc9000c4273a0 EFLAGS: 00010246
RAX: 0000000000000003 RBX: ffff88802c0c8790 RCX: ffffffff8b99c87f
RDX: 0000000000000000 RSI: ffff88802c0c8790 RDI: ffffffff90ddc8f0
RBP: ffff88802c0c8798 R08: 0000000000000000 R09: ffffed10058190f2
R10: ffff88802c0c8793 R11: 0000000000000000 R12: ffff88802c0c8790
R13: ffff88802c0c8000 R14: 0000000000000000 R15: ffff88802c0c87d0
FS: 00007ffaf56696c0(0000) GS:ffff8880d6318000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000005645e000 CR4: 0000000000352ef0
Call Trace:
<TASK>
__raw_callee_save___pv_queued_spin_unlock_slowpath+0x15/0x40
.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+0x145/0x1e0 kernel/locking/spinlock_debug.c:142
__raw_spin_unlock include/linux/spinlock_api_smp.h:168 [inline]
_raw_spin_unlock+0x1e/0x50 kernel/locking/spinlock.c:190
spin_unlock include/linux/spinlock.h:390 [inline]
hv_tlb_flush_enqueue.isra.0+0x195/0x200 arch/x86/kvm/hyperv.c:1967
kvm_hv_flush_tlb+0x17b4/0x1ae0 arch/x86/kvm/hyperv.c:2150
kvm_hv_hypercall+0xd0b/0x2350 arch/x86/kvm/hyperv.c:2629
kvm_emulate_hypercall+0x115/0x3c0 arch/x86/kvm/x86.c:10510
__vmx_handle_exit arch/x86/kvm/vmx/vmx.c:6848 [inline]
vmx_handle_exit+0x4d6/0x1ef0 arch/x86/kvm/vmx/vmx.c:6858
vcpu_enter_guest arch/x86/kvm/x86.c:11550 [inline]
vcpu_run+0x3558/0x5d50 arch/x86/kvm/x86.c:11707
kvm_arch_vcpu_ioctl_run+0x5b6/0x1890 arch/x86/kvm/x86.c:12062
kvm_vcpu_ioctl+0x730/0x1700 virt/kvm/kvm_main.c:4470
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffaf479ce59
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:00007ffaf5669028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffaf4a15fa0 RCX: 00007ffaf479ce59
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000006
RBP: 00007ffaf4832e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffaf4a16038 R14: 00007ffaf4a15fa0 R15: 00007ffcc021d3a8
</TASK>
----------------
Code disassembly (best guess), 3 bytes skipped:
0: 48 c1 ea 03 shr $0x3,%rdx
4: 0f b6 14 02 movzbl (%rdx,%rax,1),%edx
8: 4c 89 e0 mov %r12,%rax
b: 83 e0 07 and $0x7,%eax
e: 83 c0 03 add $0x3,%eax
11: 38 d0 cmp %dl,%al
13: 7c 04 jl 0x19
15: 84 d2 test %dl,%dl
17: 75 4d jne 0x66
19: 41 8b 14 24 mov (%r12),%edx
1d: 48 8d 3d 40 00 44 05 lea 0x5440040(%rip),%rdi # 0x5440064
24: 4c 89 e6 mov %r12,%rsi
* 27: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2c: e9 2f ff ff ff jmp 0xffffff60
31: 48 89 df mov %rbx,%rdi
34: 48 89 14 24 mov %rdx,(%rsp)
38: e8 17 07 e0 f6 call 0xf6e00754
---
This report is generated by a bot. It may contain errors.
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next reply other threads:[~2026-06-22 17:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-22 17:01 syzbot [this message]
2026-06-23 0:12 ` [syzbot] [kvm-x86?] WARNING in hv_tlb_flush_enqueue Sean Christopherson
2026-06-23 0:42 ` syzbot
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