syzbot


WARNING in x86_emulate_insn (2)

Status: upstream: reported C repro on 2025/11/24 14:40
Subsystems: kvm-x86
[Documentation on labels]
Reported-by: syzbot+fa52a184ebce1b30ad49@syzkaller.appspotmail.com
First crash: 47d, last: 33d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kvm-x86?] WARNING in x86_emulate_insn (2) 1 (3) 2025/11/24 21:13
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in x86_emulate_insn kvm-x86 -1 C error 309 2912d 2958d 0/29 closed as invalid on 2019/11/07 10:18
Last patch testing requests (2)
Created Duration User Patch Repo Result
2025/12/08 11:27 38m retest repro linux-next report log
2025/11/24 20:20 23m seanjc@google.com https://github.com/sean-jc/linux.git x86/emulator_no_avx report log

Sample crash report:
------------[ 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>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/24 10:36 linux-next d724c6f85e80 4fb8ef37 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in x86_emulate_insn
* Struck through repros no longer work on HEAD.