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Date:   Wed, 24 Feb 2021 13:27:10 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     syzbot <syzbot+42a71c84ef04577f1aef@syzkaller.appspotmail.com>
Cc:     dave.hansen@intel.com, hpa@zytor.com, jmattson@google.com,
        joro@8bytes.org, kirill.shutemov@linux.intel.com,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        lstoakes@gmail.com, mingo@redhat.com, pbonzini@redhat.com,
        seanjc@google.com, syzkaller-bugs@googlegroups.com,
        tglx@linutronix.de, vkuznets@redhat.com, wanpengli@tencent.com,
        x86@kernel.org
Subject: Re: general protection fault in vmx_vcpu_run (2)
Message-ID: <20210224122710.GB20344@zn.tnic>
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 <00000000000004e7d105bc091e06@google.com>
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On Tue, Feb 23, 2021 at 03:17:07PM -0800, syzbot wrote:
> syzbot has bisected this issue to:
> 
> commit 167dcfc08b0b1f964ea95d410aa496fd78adf475
> Author: Lorenzo Stoakes <lstoakes@gmail.com>
> Date:   Tue Dec 15 20:56:41 2020 +0000
> 
>     x86/mm: Increase pgt_buf size for 5-level page tables
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=13fe3ea8d00000
> start commit:   a99163e9 Merge tag 'devicetree-for-5.12' of git://git.kern..
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=10013ea8d00000

No oops here.

> console output: https://syzkaller.appspot.com/x/log.txt?x=17fe3ea8d00000

Nothing special here too.

> kernel config:  https://syzkaller.appspot.com/x/.config?x=49116074dd53b631

Tried this on two boxes, the Intel one doesn't even boot with that
config - and it is pretty standard one - and on the AMD one the
reproducer doesn't trigger anything. It probably won't because the GP
is in vmx_vcpu_run() but since the ioctls were doing something with
IRQCHIP, I thought it is probably vendor-agnostic.

So, all in all, I could use some more info on how you're reproducing and
maybe you could show the oops too.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette