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From: Peter Zijlstra <peterz@infradead.org>
To: kernel test robot <fengguang.wu@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>, LKP <lkp@01.org>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	wfg@linux.intel.com
Subject: Re: [perf/x86] 75925e1ad7:  BUG: unable to handle kernel paging request at 000045b8
Date: Fri, 22 Jan 2016 08:58:12 +0100	[thread overview]
Message-ID: <20160122075812.GM6357@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <56a1b114.H5JOWAoJgA2/uN2W%fengguang.wu@intel.com>

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@linux.intel.com>
> AuthorDate: Thu Oct 22 15:07:21 2015 -0700
> Commit:     Ingo Molnar <mingo@kernel.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.

  reply	other threads:[~2016-01-22  7:58 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-22  4:33 kernel test robot
2016-01-22  7:58 ` Peter Zijlstra [this message]
2016-01-23  1:27 ` Andi Kleen

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