[syzbot ci] Re: KVM: x86: Unconditionally recompute CR8 intercept on PPR update

syzbot ci <[email protected]>
Newsgroups dev.linux.lists.syzbot,org.kernel.vger.kvm,org.kernel.vger.linux-kernel,org.kernel.vger.stable
Message-ID <[email protected]>
syzbot ci has tested the following series

[v2] KVM: x86: Unconditionally recompute CR8 intercept on PPR update
https://lore.kernel.org/all/[email protected]
* [PATCH v2] KVM: x86: Unconditionally recompute CR8 intercept on PPR update

and found the following issue:
WARNING in vmx_update_cr8_intercept

Full report is available here:
https://ci.syzbot.org/series/d94aebb2-8082-4777-ab08-5c3a0d680bed

***

WARNING in vmx_update_cr8_intercept

tree:      linux-next
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next
base:      c1f7303302927f9cbf4efedf70f0512cde168c65
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/8f417377-50a6-450a-8ce0-a83de33b8c6d/config
syz repro: https://ci.syzbot.org/findings/62a660e6-a9b1-42ca-9cf0-7aadd2f5d292/syz_repro

------------[ cut here ]------------
debug_locks && !(lock_is_held(&(&vcpu->mutex)->dep_map) || !refcount_read(&vcpu->kvm->users_count))
WARNING: arch/x86/kvm/vmx/nested.h:61 at get_vmcs12 arch/x86/kvm/vmx/nested.h:60 [inline], CPU#0: syz.2.19/5879
WARNING: arch/x86/kvm/vmx/nested.h:61 at vmx_update_cr8_intercept+0x3de/0x4e0 arch/x86/kvm/vmx/vmx.c:6879, CPU#0: syz.2.19/5879
Modules linked in:
CPU: 0 UID: 0 PID: 5879 Comm: syz.2.19 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:get_vmcs12 arch/x86/kvm/vmx/nested.h:60 [inline]
RIP: 0010:vmx_update_cr8_intercept+0x3de/0x4e0 arch/x86/kvm/vmx/vmx.c:6879
Code: 0b 90 e9 f1 fe ff ff e8 30 12 69 00 90 0f 0b 90 e9 59 fe ff ff e8 22 12 69 00 e8 ad 86 d6 ff e9 ca fe ff ff e8 13 12 69 00 90 <0f> 0b 90 e9 fc fc ff ff e8 05 12 69 00 e8 90 86 d6 ff eb a7 48 c7
RSP: 0018:ffffc9000271f758 EFLAGS: 00010293
RAX: ffffffff815d048d RBX: ffff888113380000 RCX: ffff8881142b8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 00000000ffffffff R08: ffff8881114d9703 R09: 1ffff1102229b2e0
R10: dffffc0000000000 R11: ffffed102229b2e1 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff888116d0bca0 R15: 0000000000000001
FS:  00007ff34d6b86c0(0000) GS:ffff88818dc9b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc75e78ae8 CR3: 000000010c609000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 apic_update_ppr arch/x86/kvm/lapic.c:984 [inline]
 kvm_lapic_reset+0x1c24/0x2980 arch/x86/kvm/lapic.c:3023
 kvm_vcpu_reset+0x44c/0x1bf0 arch/x86/kvm/x86.c:12986
 kvm_arch_vcpu_create+0x746/0x8b0 arch/x86/kvm/x86.c:12847
 kvm_vm_ioctl_create_vcpu+0x428/0x930 virt/kvm/kvm_main.c:4201
 kvm_vm_ioctl+0x893/0xd50 virt/kvm/kvm_main.c:5159
 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: 0033:0x7ff34c79ce59
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:00007ff34d6b8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ff34ca15fa0 RCX: 00007ff34c79ce59
RDX: 0000000000000002 RSI: 000000000000ae41 RDI: 0000000000000004
RBP: 00007ff34c832d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff34ca16038 R14: 00007ff34ca15fa0 R15: 00007ffe4bc28aa8
 </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: [email protected]

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