Re: [syzbot] [kvm?] WARNING in __kvm_gpc_refresh

[Sean Christopherson]

On Mon, Mar 18, 2024, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    277100b3d5fe Merge tag 'block-6.9-20240315' of git://git.k..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17c96aa5180000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=1c6662240382da2
> dashboard link: https://syzkaller.appspot.com/bug?extid=106a4f72b0474e1d1b33
> compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14358231180000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=110ed231180000
> 
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-277100b3.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/6872e049b27c/vmlinux-277100b3.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/68ec7230df0f/bzImage-277100b3.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+106a4f72b0474e1d1b33@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 5192 at arch/x86/kvm/../../../virt/kvm/pfncache.c:247 __kvm_gpc_refresh+0x15e2/0x2200 arch/x86/kvm/../../../virt/kvm/pfncache.c:247

The WARN is due to a new sanity check that exposed an old wart.  I'll get a patch
posted later today.