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From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Wanpeng Li <kernellwp@gmail.com>,
	syzbot <syzbot+dff25ee91f0c7d5c1695@syzkaller.appspotmail.com>
Cc: Borislav Petkov <bp@alien8.de>,
	devel@linuxdriverproject.org,
	Haiyang Zhang <haiyangz@microsoft.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm <kvm@vger.kernel.org>, "K. Y. Srinivasan" <kys@microsoft.com>,
	LKML <linux-kernel@vger.kernel.org>,
	mikelley@microsoft.com, Ingo Molnar <mingo@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Radim Krcmar <rkrcmar@redhat.com>,
	Sasha Levin <sashal@kernel.org>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	syzkaller-bugs@googlegroups.com,
	Thomas Gleixner <tglx@linutronix.de>,
	Wanpeng Li <wanpengli@tencent.com>,
	the arch/x86 maintainers <x86@kernel.org>
Subject: Re: general protection fault in __apic_accept_irq
Date: Thu, 05 Sep 2019 15:11:33 +0200	[thread overview]
Message-ID: <87imq6khve.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <CANRm+CxBdFjVrYzAe_Rs=v6BMSq9Gx+ngDrEitK6aez=kMq2XQ@mail.gmail.com>

Wanpeng Li <kernellwp@gmail.com> writes:

> On Thu, 5 Sep 2019 at 16:53, syzbot
> <syzbot+dff25ee91f0c7d5c1695@syzkaller.appspotmail.com> wrote:
>>
>> Hello,
>>
>> syzbot found the following crash on:
>>
>> HEAD commit:    3b47fd5c Merge tag 'nfs-for-5.3-4' of git://git.linux-nfs...
>> git tree:       upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=124af12a600000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=144488c6c6c6d2b6
>> dashboard link: https://syzkaller.appspot.com/bug?extid=dff25ee91f0c7d5c1695
>> compiler:       clang version 9.0.0 (/home/glider/llvm/clang
>> 80fee25776c2fb61e74c1ecb1a523375c2500b69)
>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10954676600000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1752fe0a600000
>>
>> The bug was bisected to:
>>
>> commit 0aa67255f54df192d29aec7ac6abb1249d45bda7
>> Author: Vitaly Kuznetsov <vkuznets@redhat.com>
>> Date:   Mon Nov 26 15:47:29 2018 +0000
>>
>>      x86/hyper-v: move synic/stimer control structures definitions to
>> hyperv-tlfs.h
>>
>> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=156128c1600000
>> console output: https://syzkaller.appspot.com/x/log.txt?x=136128c1600000
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+dff25ee91f0c7d5c1695@syzkaller.appspotmail.com
>> Fixes: 0aa67255f54d ("x86/hyper-v: move synic/stimer control structures
>> definitions to hyperv-tlfs.h")
>>
>> kvm [9347]: vcpu0, guest rIP: 0xcc Hyper-V uhandled wrmsr: 0x40000004 data
>> 0x94
>> kvm [9347]: vcpu0, guest rIP: 0xcc Hyper-V uhandled wrmsr: 0x40000004 data
>> 0x48c
>> kvm [9347]: vcpu0, guest rIP: 0xcc Hyper-V uhandled wrmsr: 0x40000004 data
>> 0x4ac
>> kvm [9347]: vcpu0, guest rIP: 0xcc Hyper-V uhandled wrmsr: 0x40000005 data
>> 0x1520
>> kvm [9347]: vcpu0, guest rIP: 0xcc Hyper-V uhandled wrmsr: 0x40000006 data
>> 0x15d4
>> kvm [9347]: vcpu0, guest rIP: 0xcc Hyper-V uhandled wrmsr: 0x40000007 data
>> 0x15c4
>> kasan: CONFIG_KASAN_INLINE enabled
>> kasan: GPF could be caused by NULL-ptr deref or user memory access
>> general protection fault: 0000 [#1] PREEMPT SMP KASAN
>> CPU: 0 PID: 9347 Comm: syz-executor665 Not tainted 5.3.0-rc7+ #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> Google 01/01/2011
>> RIP: 0010:__apic_accept_irq+0x46/0x740 arch/x86/kvm/lapic.c:1029
>
> Thanks for the report, I found the root cause, will send a patch soon.
>

I'm really interested in how any issue can be caused by 0aa67255f54d as
we just moved some definitions from a c file to a common header... (ok,
we did more than that, some structures gained '__packed' but it all
still seems legitimate to me and I can't recall any problems with
genuine Hyper-V...)

-- 
Vitaly

  reply	other threads:[~2019-09-05 13:11 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-05  8:28 general protection fault in __apic_accept_irq syzbot
2019-09-05  9:25 ` Wanpeng Li
2019-09-05 13:11   ` Vitaly Kuznetsov [this message]
2019-09-06  3:41     ` Wanpeng Li

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