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From: Masami Hiramatsu <mhiramat@redhat.com>
To: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	ananth@in.ibm.com, David Miller <davem@davemloft.net>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] kprobes: disable preempt for module_text_address()
Date: Wed, 05 Nov 2008 18:07:49 -0500	[thread overview]
Message-ID: <49122745.4090004@redhat.com> (raw)
In-Reply-To: <4912222F.9040605@ct.jp.nec.com>

Hiroshi Shimamoto wrote:
>>  	if (probed_mod) {
>> -		struct module *calling_mod = module_text_address(called_from);
>> +		struct module *calling_mod;
>> +		calling_mod = __module_text_address(called_from);
>>  		/*
>>  		 * We must allow modules to probe themself and in this case
>>  		 * avoid incrementing the module refcount, so as to allow
>>  		 * unloading of self probing modules.
>>  		 */
>>  		if (calling_mod && calling_mod != probed_mod) {
> 
> One question, off topic.
> If calling_mod is NULL, no try_module_get(), is that OK?

Good question. Currently, kprobes is called only from kernel modules,
so calling_mod should be always !NULL.
However, it should be fixed, because the logic is not correct.

Thank you,

-- 
Masami Hiramatsu

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

e-mail: mhiramat@redhat.com


  reply	other threads:[~2008-11-05 23:09 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-04  5:56 Lai Jiangshan
2008-11-04 14:28 ` Ananth N Mavinakayanahalli
2008-11-05  0:53   ` Lai Jiangshan
2008-11-05  1:27 ` Masami Hiramatsu
2008-11-05  1:47   ` Lai Jiangshan
2008-11-05 19:30     ` Hiroshi Shimamoto
2008-11-05 21:40     ` Masami Hiramatsu
2008-11-05 22:46       ` Hiroshi Shimamoto
2008-11-05 23:07         ` Masami Hiramatsu [this message]
2008-11-06  0:06           ` [PATCH] kprobes: bugfix: try_module_get even if calling_mod is NULL Masami Hiramatsu
2008-11-07  1:00             ` Andrew Morton
2008-11-07  2:28               ` Masami Hiramatsu
2008-11-07  2:54                 ` Andrew Morton
2008-11-07  4:46                   ` Ananth N Mavinakayanahalli
2008-11-06  1:06       ` [PATCH] kprobes: disable preempt for module_text_address() Lai Jiangshan
2008-11-06 15:37         ` [PATCH] kprobes: disable preempt for module_text_address() and kernel_text_address() Masami Hiramatsu
2008-11-07  0:32           ` Lai Jiangshan

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