[syzbot] [kvm-x86?] WARNING in x86_emulate_insn (2)

syzbot
2025-11-24T14:40:33Z

Hello,

syzbot found the following issue on:

HEAD commit: d724c6f85e80 Add linux-next specific files for 20251121
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11513612580000
kernel config: https://syzkaller.appspot.com/x/.config?x=763fb984aa266726
dashboard link: https://syzkaller.appspot.com/bug?extid=fa52a184ebce1b30ad49
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=165638b4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15c00e58580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b2f349c65e3c/disk-d724c6f8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/aba40ae987ce/vmlinux-d724c6f8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0b98fbfe576f/bzImage-d724c6f8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fa52a184ebce1b30ad49@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: arch/x86/kvm/emulate.c:5560 at x86_emulate_insn+0x2909/0x41a0 arch/x86/kvm/emulate.c:5560, CPU#1: syz.1.2382/16268
Modules linked in:
CPU: 1 UID: 0 PID: 16268 Comm: syz.1.2382 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:x86_emulate_insn+0x2909/0x41a0 arch/x86/kvm/emulate.c:5560
Code: 36 31 ff 44 89 f6 e8 66 99 77 00 45 85 f6 0f 84 05 02 00 00 e8 18 95 77 00 41 bf 01 00 00 00 e9 ef e0 ff ff e8 08 95 77 00 90 <0f> 0b 90 48 8b 44 24 50 42 80 3c 20 00 48 8b 5c 24 48 74 08 48 89
RSP: 0018:ffffc9000d6ff6c0 EFLAGS: 00010293
RAX: ffffffff814a8468 RBX: 000304000010220a RCX: ffff88807d930000
RDX: 0000000000000000 RSI: 00000000000000ff RDI: 000000000000001f
RBP: ffffc9000d6ff7d0 R08: ffff88807d930000 R09: 0000000000000002
R10: 0000000000000006 R11: 0000000000000000 R12: dffffc0000000000
R13: 1ffff92001adfee8 R14: 00000000000000ff R15: ffff888060266780
FS: 00007f90f1e156c0(0000) GS:ffff888125b6f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000745ec000 CR4: 00000000003526f0
Call Trace:
<TASK>
x86_emulate_instruction+0xea7/0x20b0 arch/x86/kvm/x86.c:9521
kvm_arch_vcpu_ioctl_run+0x1404/0x1cd0 arch/x86/kvm/x86.c:11960
kvm_vcpu_ioctl+0x99a/0xed0 virt/kvm/kvm_main.c:4477
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+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f90f0f8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f90f1e15038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f90f11e6090 RCX: 00007f90f0f8f749
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007f90f1013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f90f11e6128 R14: 00007f90f11e6090 R15: 00007ffc7b4d1758
</TASK>

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