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Date: Thu, 11 Dec 2008 15:10:03 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: hidehiro.kawai.ez@hitachi.com, kosaki.motohiro@jp.fujitsu.com,
       linux-kernel@vger.kernel.org, roland@redhat.com,
       yumiko.sugita.yf@hitachi.com, satoshi.oshima.fk@hitachi.com
Subject: Re: [PATCH] coredump_filter: enable to change the default filter
Message-Id: <20081211151003.00572e04.akpm@linux-foundation.org>
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On Thu, 11 Dec 2008 15:46:49 +0900 (JST)
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:

> Hi
> 
> > This patch introduces new kernel parameter `coredump_filter'.
> > Setting a value to this parameter causes the default bitmask
> > of coredump_filter to be changed.
> > 
> > It is useful for users to change coredump_filter settings for
> > the whole system at boot time.  Without this parameter, users
> > have to change coredump_filter settings for each /proc/<pid>/
> > in an initializing script.
> 
> I think this patch only useful on following situation, right?
> 
>   - Administrator can't change rc script.
>   - Administrator can change boot parameter.
> 
> 
> When happen above situation?
> or, you intent to init process debugging?

Yes, this can be implemented in userspace by setting init's filter
before init forks any other processes.

I can understand the practical problems with that form of implementation
however :(


Or does the patch change other behaviour?  Say, when mm_init() is
called by a kernel thread (current->mm==NULL)?  call_usermodehelper(),
for example?

If so, then setting init's filter doesn't cover that case.
--
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