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From: "Lan, Tianyu" <tianyu.lan@intel.com>
To: Wanpeng Li <kernellwp@gmail.com>, Tianyu Lan <lantianyu1986@gmail.com>
Cc: Jim Mattson <jmattson@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	syzbot 
	<bot+75375385991b4f8c599704a10849863c586ea284@syzkaller.appspotmail.com>,
	"H. Peter Anvin" <hpa@zytor.com>, kvm <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Radim Krcmar <rkrcmar@redhat.com>,
	syzkaller-bugs@googlegroups.com,
	Thomas Gleixner <tglx@linutronix.de>,
	the arch/x86 maintainers <x86@kernel.org>
Subject: Re: Re: WARNING in x86_emulate_insn
Date: Sat, 9 Dec 2017 13:44:02 +0800	[thread overview]
Message-ID: <919b87e5-502d-7445-454a-85243b450f1c@intel.com> (raw)
In-Reply-To: <CANRm+Cxn1pzHmT6sqm=MGSkrEMBzzrrZ3dwNz_m6J9bDY3jFDQ@mail.gmail.com>


On 12/8/2017 5:27 PM, Wanpeng Li wrote:
> 2017-12-08 16:28 GMT+08:00 Tianyu Lan <lantianyu1986@gmail.com>:
>> Hi Jim&Wanpeng:
>>           Thanks for your help.
>>
>> 2017-12-08 5:25 GMT+08:00 Jim Mattson <jmattson@google.com>:
>>> Try disabling the module parameter, "unrestricted_guest." Make sure
>>> that the module parameter, "emulate_invalid_guest_state" is enabled.
>>> This combination allows userspace to feed invalid guest state into the
>>> in-kernel emulator.
>>
>> Yes, you are right. I need to disable unrestricted_guest to reproduce the issue.
> 
> I can observe ctxt->exception.vector == 0xff which triggers Dmitry's
> report. Do you figure out the reason?
> 

Yes, this is caused by that emulation callback returns error code while
not emulate exception and not set exception vector.
ctxt->exception.vector is default to be 0xff in emulate instruction code
path.

  reply	other threads:[~2017-12-09  5:44 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-05 20:07 WARNING in x86_emulate_insn syzbot
2017-12-07  0:44 ` Wanpeng Li
2017-12-07  6:25   ` Dmitry Vyukov
2017-12-07  7:49     ` 蓝天宇
2017-12-07  7:52       ` Wanpeng Li
2017-12-07 10:40         ` Wanpeng Li
2017-12-07 21:25           ` Jim Mattson
2017-12-08  8:28             ` Tianyu Lan
2017-12-08  8:44               ` Ingo Molnar
2017-12-08  8:48                 ` Tianyu Lan
2017-12-08  9:27               ` Wanpeng Li
2017-12-09  5:44                 ` Lan, Tianyu [this message]
2017-12-11 22:45               ` Paolo Bonzini
2017-12-12  8:50                 ` Lan Tianyu
2017-12-08  3:22 ` syzbot
2017-12-08  3:33   ` Wanpeng Li

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