WARNING in nested_vmx_vmexit

Status: upstream: reported C repro on 2026/10/18 07:56
Reported-by: syzbot+4b87bead6f2de60d5be6@syzkaller.appspotmail.com
First crash: 18h54m, last: 15h19m
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-12 WARNING in nested_vmx_vmexit origin:lts -1 syz, C 2 7d18h 361d 0/1 premoderation: reported C repro on 2025/10/22 16:54
upstream WARNING in nested_vmx_vmexit kvm-x86 -1 syz, C done 101 1761d 1778d 20/29 fixed on 2022/03/08 16:11

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5430 at arch/x86/kvm/vmx/nested.c:4785 nested_vmx_vmexit+0x1a15/0x2ce0 arch/x86/kvm/vmx/nested.c:4785
Modules linked in:
CPU: 0 PID: 5430 Comm: syz.4.233 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:nested_vmx_vmexit+0x1a15/0x2ce0 arch/x86/kvm/vmx/nested.c:4785
Code: 84 24 00 01 00 00 0f 85 9a 03 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 85 7d 5c 00 e9 fe f4 ff ff e8 7b 7d 5c 00 <0f> 0b e9 f4 e6 ff ff 0f 1f 44 00 00 b8 00 44 00 00 4c 8b 64 24 18
RSP: 0018:ffffc90003bf74e0 EFLAGS: 00010293
RAX: ffffffff8125c905 RBX: ffff88805ba3ca9b RCX: ffff888023ad3c00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff88805ba3ca9c
RBP: ffffc90003bf7630 R08: ffff88805ba3a7ff R09: 1ffff1100b7474ff
R10: dffffc0000000000 R11: ffffed100b747500 R12: ffff88805ba3a7c0
R13: dffffc0000000000 R14: ffff88805ba3ca30 R15: ffff88805ba3a7c0
FS:  00007f96515b06c0(0000) GS:ffff8880b8c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007cc94000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 vcpu_enter_guest+0x4a14/0x7a90 arch/x86/kvm/x86.c:10695
 vcpu_run arch/x86/kvm/x86.c:11125 [inline]
 kvm_arch_vcpu_ioctl_run+0xf2c/0x22c0 arch/x86/kvm/x86.c:11349
 kvm_vcpu_ioctl+0x986/0xd00 virt/kvm/kvm_main.c:4123
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f965079e559
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:00007f96515b0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9650a26090 RCX: 00007f965079e559
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000006
RBP: 00007f9650835ab8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9650a26128 R14: 00007f9650a26090 R15: 00007ffe57ed8ce8
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/18 11:30 linux-6.1.y 79807e970724 432c0077 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in nested_vmx_vmexit
2026/10/18 10:40 linux-6.1.y 79807e970724 432c0077 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in nested_vmx_vmexit
2026/10/18 09:46 linux-6.1.y 79807e970724 432c0077 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in nested_vmx_vmexit
2026/10/18 08:51 linux-6.1.y 79807e970724 432c0077 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in nested_vmx_vmexit
2026/10/18 07:55 linux-6.1.y 79807e970724 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in nested_vmx_vmexit
* Struck through repros no longer work on HEAD.