[syzbot] [kvm-x86?] WARNING in vcpu_run (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8c13415c8a43 Merge tag 'media/v7.2-1' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12ec001c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d4e6991ab3edc95e
dashboard link: https://syzkaller.appspot.com/bug?extid=dd769db18693736eee89
compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=157ce8ea580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1176e566580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/27752fb81380/disk-8c13415c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/192b476e0df1/vmlinux-8c13415c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ba635e3d5aec/bzImage-8c13415c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dd769d...@syzkaller.appspotmail.com

------------[ cut here ]------------
irq == -1
WARNING: arch/x86/kvm/x86.c:10860 at kvm_check_and_inject_events arch/x86/kvm/x86.c:10860 [inline], CPU#0: syz.4.1716/11103
WARNING: arch/x86/kvm/x86.c:10860 at vcpu_enter_guest arch/x86/kvm/x86.c:11356 [inline], CPU#0: syz.4.1716/11103
WARNING: arch/x86/kvm/x86.c:10860 at vcpu_run+0x57ec/0x7950 arch/x86/kvm/x86.c:11770, CPU#0: syz.4.1716/11103
Modules linked in:
CPU: 0 UID: 0 PID: 11103 Comm: syz.4.1716 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:kvm_check_and_inject_events arch/x86/kvm/x86.c:10860 [inline]
RIP: 0010:vcpu_enter_guest arch/x86/kvm/x86.c:11356 [inline]
RIP: 0010:vcpu_run+0x57ec/0x7950 arch/x86/kvm/x86.c:11770
Code: b5 ff ff 89 d1 80 e1 07 38 c1 0f 8c 64 b1 ff ff 48 8b 7c 24 58 e8 a4 66 eb 00 48 8b 54 24 58 e9 50 b1 ff ff e8 b5 47 7e 00 90 <0f> 0b 90 4c 8b 64 24 10 e9 4c e7 ff ff e8 a2 47 7e 00 90 0f 0b 90
RSP: 0018:ffffc90006e375e0 EFLAGS: 00010293
RAX: ffffffff8147d98b RBX: ffff88805b402cc0 RCX: ffff88807bca5d00
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 00000000ffffffff
RBP: ffffc90006e379b0 R08: ffff88805b402c57 R09: 1ffff1100b68058a
R10: dffffc0000000000 R11: ffffed100b68058b R12: 00000000ffffffff
R13: ffff88805b402ca0 R14: 0000000000000001 R15: dffffc0000000000
FS: 0000555579916500(0000) GS:ffff88812525d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1c74672780 CR3: 0000000075b22000 CR4: 00000000003526f0
Call Trace:
<TASK>
kvm_arch_vcpu_ioctl_run+0x1193/0x2070 arch/x86/kvm/x86.c:12125
kvm_vcpu_ioctl+0xa61/0xfd0 virt/kvm/kvm_main.c:4470
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1c7479ce59
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:00007ffdeb74dbf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1c74a15fa0 RCX: 00007f1c7479ce59
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000006
RBP: 00007f1c74832e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1c74a15fac R14: 00007f1c74a15fa0 R15: 00007f1c74a15fa0
</TASK>


---
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#syz undup

[Sean Christopherson]

On Fri, Jun 19, 2026, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 8c13415c8a43 Merge tag 'media/v7.2-1' of git://git.kernel...
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=12ec001c580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d4e6991ab3edc95e
> dashboard link: https://syzkaller.appspot.com/bug?extid=dd769db18693736eee89
> compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=157ce8ea580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1176e566580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/27752fb81380/disk-8c13415c.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/192b476e0df1/vmlinux-8c13415c.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/ba635e3d5aec/bzImage-8c13415c.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+dd769d...@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> irq == -1
> WARNING: arch/x86/kvm/x86.c:10860 at kvm_check_and_inject_events arch/x86/kvm/x86.c:10860 [inline], CPU#0: syz.4.1716/11103
> WARNING: arch/x86/kvm/x86.c:10860 at vcpu_enter_guest arch/x86/kvm/x86.c:11356 [inline], CPU#0: syz.4.1716/11103
> WARNING: arch/x86/kvm/x86.c:10860 at vcpu_run+0x57ec/0x7950 arch/x86/kvm/x86.c:11770, CPU#0: syz.4.1716/11103

#syz test

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d9d51803b7b2..14a62c2ce3ad 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10797,10 +10797,12 @@ static int kvm_check_and_inject_events(struct kvm_vcpu *vcpu,
if (r) {
int irq = kvm_cpu_get_interrupt(vcpu);

- if (!WARN_ON_ONCE(irq == -1)) {
+ if (likely(irq != -1)) {
kvm_queue_interrupt(vcpu, irq, false);
kvm_x86_call(inject_irq)(vcpu, false);
WARN_ON(kvm_x86_call(interrupt_allowed)(vcpu, true) < 0);
+ } else {
+ WARN_ON_ONCE(!pic_in_kernel(vcpu->kvm));
}
}
if (kvm_cpu_has_injectable_intr(vcpu))

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
lost connection to test machine



Tested on:

commit: ab9de95c Merge tag 'rust-7.2-2' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=148b430e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=86ba763b42fa66a
dashboard link: https://syzkaller.appspot.com/bug?extid=dd769db18693736eee89
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=10627ce6580000