[syzbot ci] Re: Enable FRED with KVM VMX

syzbot ci
2025-10-14T06:13:13Z

syzbot ci has tested the following series

[v8] Enable FRED with KVM VMX
https://lore.kernel.org/all/20251014010950.1568389-1-xin@zytor.com
* [PATCH v8 01/21] KVM: VMX: Add support for the secondary VM exit controls
* [PATCH v8 02/21] KVM: VMX: Initialize VM entry/exit FRED controls in vmcs_config
* [PATCH v8 03/21] KVM: VMX: Disable FRED if FRED consistency checks fail
* [PATCH v8 04/21] x86/cea: Prefix event stack names with ESTACK_
* [PATCH v8 05/21] x86/cea: Export API for per-CPU exception stacks for KVM
* [PATCH v8 06/21] KVM: VMX: Initialize VMCS FRED fields
* [PATCH v8 07/21] KVM: VMX: Set FRED MSR intercepts
* [PATCH v8 08/21] KVM: VMX: Save/restore guest FRED RSP0
* [PATCH v8 09/21] KVM: VMX: Add support for saving and restoring FRED MSRs
* [PATCH v8 10/21] KVM: x86: Add a helper to detect if FRED is enabled for a vCPU
* [PATCH v8 11/21] KVM: VMX: Virtualize FRED event_data
* [PATCH v8 12/21] KVM: VMX: Virtualize FRED nested exception tracking
* [PATCH v8 13/21] KVM: x86: Save/restore the nested flag of an exception
* [PATCH v8 14/21] KVM: x86: Mark CR4.FRED as not reserved
* [PATCH v8 15/21] KVM: VMX: Dump FRED context in dump_vmcs()
* [PATCH v8 16/21] KVM: x86: Advertise support for FRED
* [PATCH v8 17/21] KVM: nVMX: Add support for the secondary VM exit controls
* [PATCH v8 18/21] KVM: nVMX: Add FRED VMCS fields to nested VMX context handling
* [PATCH v8 19/21] KVM: nVMX: Add FRED-related VMCS field checks
* [PATCH v8 20/21] KVM: nVMX: Add prerequisites to SHADOW_FIELD_R[OW] macros
* [PATCH v8 21/21] KVM: nVMX: Allow VMX FRED controls

and found the following issue:
WARNING in vmread_error

Full report is available here:
https://ci.syzbot.org/series/706e7cbc-a7af-4357-af68-194e1c883968

***

WARNING in vmread_error

tree: torvalds
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base: 0d97f2067c166eb495771fede9f7b73999c67f66
arch: amd64
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
config: https://ci.syzbot.org/builds/0033ed68-ef22-4ef4-a630-0d101fb2cb8e/config
C repro: https://ci.syzbot.org/findings/a19ef524-0065-4a83-abb5-c42a195ec916/c_repro
syz repro: https://ci.syzbot.org/findings/a19ef524-0065-4a83-abb5-c42a195ec916/syz_repro

------------[ cut here ]------------
vmread failed: field=281a
WARNING: CPU: 0 PID: 5954 at arch/x86/kvm/vmx/vmx.c:425 vmread_error+0x7e/0x90 arch/x86/kvm/vmx/vmx.c:425
Modules linked in:
CPU: 0 UID: 0 PID: 5954 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:vmread_error+0x7e/0x90 arch/x86/kvm/vmx/vmx.c:425
Code: dc 63 8b 48 89 de 5b 5d e9 cf de cf ff e8 0a 62 68 00 c6 05 4c 67 30 0e 01 90 48 c7 c7 80 db 63 8b 48 89 de e8 03 7f 2b 00 90 <0f> 0b 90 90 eb 98 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90
RSP: 0018:ffffc90004d66f28 EFLAGS: 00010246
RAX: c305e84bb7041f00 RBX: 000000000000281a RCX: ffff888109e48000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc90004d674a8 R08: ffff888121024293 R09: 1ffff11024204852
R10: dffffc0000000000 R11: ffffed1024204853 R12: dffffc0000000000
R13: ffff8881152e0000 R14: ffff88811292a30f R15: ffff88811292a000
FS: 0000555576a3b500(0000) GS:ffff88818e70e000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001bda0c000 CR4: 0000000000352ef0
Call Trace:
<TASK>
__vmcs_readl arch/x86/kvm/vmx/vmx_ops.h:111 [inline]
vmcs_read64 arch/x86/kvm/vmx/vmx_ops.h:177 [inline]
nested_vmx_enter_non_root_mode+0xa0ef/0xbb20 arch/x86/kvm/vmx/nested.c:3834
nested_vmx_run+0x5f7/0xc40 arch/x86/kvm/vmx/nested.c:4053
__vmx_handle_exit arch/x86/kvm/vmx/vmx.c:6821 [inline]
vmx_handle_exit+0x10a4/0x18c0 arch/x86/kvm/vmx/vmx.c:6838
vcpu_enter_guest arch/x86/kvm/x86.c:11575 [inline]
vcpu_run+0x446f/0x6fb0 arch/x86/kvm/x86.c:11733
kvm_arch_vcpu_ioctl_run+0xfc9/0x1940 arch/x86/kvm/x86.c:12072
kvm_vcpu_ioctl+0x95c/0xe90 virt/kvm/kvm_main.c:4476
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: 0033:0x7f22ca18eec9
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:00007fff1aacefa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f22ca3e5fa0 RCX: 00007f22ca18eec9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007f22ca211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f22ca3e5fa0 R14: 00007f22ca3e5fa0 R15: 0000000000000003
</TASK>

***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
Tested-by: syzbot@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.