linux-kernel - Re: [PATCH] x86: Use is_kprobe

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Message-ID: <477C5474.3040302@redhat.com>
Date:	Wed, 02 Jan 2008 22:20:20 -0500
From:	Masami Hiramatsu <mhiramat@...hat.com>
To:	Harvey Harrison <harvey.harrison@...il.com>
CC:	Ingo Molnar <mingo@...e.hu>, qbarnes <qbarnes@...il.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Jim Keniston <jkenisto@...ibm.com>, davem@...emloft.net,
	Keshavamurthy Anil S <anil.s.keshavamurthy@...el.com>
Subject: Re: [PATCH] x86: Use is_kprobe_fault to better match usage

Harvey Harrison wrote:
> On Wed, 2008-01-02 at 21:36 -0500, Masami Hiramatsu wrote:
>> Hi Harvey,
>>
>> Harvey Harrison wrote:
>>> Currently the notify_page_fault helper is used to test it the page
>>> fault was caused by a kprobe causing an early return from do_page_fault.
>>>
>>> Change the name of the helper to is_kprobe_fault to match the usage and
>>> remove the preempt_disable/enable pair around kprobe_running() with an
>>> explicit test for preemption.  The idea for this comes from a patch
>>> by Quentin Barnes to kprobes.c
>> Sure, that's right.
>> However, since other architectures also have notify_page_fault(),
>> I think all of those code might better be changed same time for
>> maintainability.
>>
> 
> How about a static inline in linux/kprobes.h with a big comment above
> about when/why the !preemptible() check is sufficient?

Hmm, fault handling depends on the architecture. But current
notify_page_fault()s are very similar. I think unifying it is good idea.
We will be happy to review that if you send it.

Many thanks!

> 
> Harvey
> 
> 
> 

-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@...hat.com, masami.hiramatsu.pt@...achi.com

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