linux-kernel - Re: [perf/x86] 75925e1ad7: BUG: unable to handle kernel paging request at 000045b8

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20160122075812.GM6357@twins.programming.kicks-ass.net>
Date:	Fri, 22 Jan 2016 08:58:12 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	kernel test robot <fengguang.wu@...el.com>
Cc:	Andi Kleen <ak@...ux.intel.com>, LKP <lkp@...org>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
	wfg@...ux.intel.com
Subject: Re: [perf/x86] 75925e1ad7:  BUG: unable to handle kernel paging
 request at 000045b8

On Fri, Jan 22, 2016 at 12:33:24PM +0800, kernel test robot wrote:
> Greetings,
> 
> 0day kernel testing robot got the below dmesg and the first bad commit is
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> 
> commit 75925e1ad7f5a4e867bd14ff8e7f114ea1596434
> Author:     Andi Kleen <ak@...ux.intel.com>
> AuthorDate: Thu Oct 22 15:07:21 2015 -0700
> Commit:     Ingo Molnar <mingo@...nel.org>
> CommitDate: Mon Nov 23 09:58:25 2015 +0100
> 
>     perf/x86: Optimize stack walk user accesses
>     
>     Change the perf user stack walking to use the new
>     __copy_from_user_nmi(), and split each access into word sized transfer
>     sizes. This allows to inline the complete access and optimize it all
>     into a single load.

Andi, please have a look at this. Also note that x86_64
__copy_from_user_nocheck() actually supports .size=16.