linux-kernel - Re: [qemu64,+smep,+smap] Kernel panic - not syncing: No working init found.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <52FCE74A.4010000@zytor.com>
Date:	Thu, 13 Feb 2014 07:39:54 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Fengguang Wu <fengguang.wu@...el.com>, kvm <kvm@...r.kernel.org>
CC:	LKML <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [qemu64,+smep,+smap] Kernel panic - not syncing: No working init
 found.

On 02/13/2014 06:55 AM, H. Peter Anvin wrote:
> On 02/13/2014 04:45 AM, Fengguang Wu wrote:
>> Greetings,
>>
>> I find that when running
>>
>>         qemu-system-x86_64 -cpu qemu64,+smep,+smap
>>
>> Some kernels will 100% produce this error, where the error code
>> -13,-14 are -EACCES and -EFAULT:
>>
>> Any ideas?
>>
> 
> I notice this is a non-SMAP kernel:
> 
> # CONFIG_X86_SMAP is not set
> 
> If the kernel turns on SMAP in CR4 even though SMAP isn't enabled in the
> kernel, that is a kernel bug.  If Qemu enforces SMAP even if it is
> turned off in CR4, that would be a Qemu bug.  I have reproduced the
> failure locally and an am considering both possibilities now.
> 

So we do turn on the bit in CR4 even with SMAP compiled out.  This is a
bug.  However, I still get the same failure even with that bug fixed
(and qemu "info registers" verify that it is, indeed, not set) so I'm
wondering if there is a bug in Qemu as well.  However, staring at the
code in Qemu I don't see where that bug would be...

	-hpa


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/