linux-kernel - Re: [PATCH] call_usermodehelper_setup() should use GFP

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Message-Id: <20080508012957.c778c8e7.akpm@linux-foundation.org>
Date:	Thu, 8 May 2008 01:29:57 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	Li Zefan <lizf@...fujitsu.com>, Paul Menage <menage@...gle.com>,
	Jeremy Fitzhardinge <jeremy@...source.com>,
	Andi Kleen <ak@...e.de>, LKML <linux-kernel@...r.kernel.org>,
	Rusty Russell <rusty@...tcorp.com.au>
Subject: Re: [PATCH] call_usermodehelper_setup() should use GFP_KERNEL

On Thu, 08 May 2008 16:31:29 +0900 KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com> wrote:

> > KOSAKI Motohiro wrote:
> > > Now, call_usermodehelper_setup() use GFP_ATOMIC.
> > > but it is slighly odd.
> > > because call_usermodehelper() is always called process context.
> > > 
> > 
> > Are you sure? I found the following call chain:
> > 
> >   static irqreturn_t power_handler(int irq, void *dev_id)
> >   ->orderly_poweroff(true);
> >     ->call_usermodehelper_setup()
> 
> sorry, you are right.
> I'll make patch again.

How many times do we have to make this mistake :(

Only the caller knows what allocation mode the callee can use. 
call_usermodehelper_setup() should be extended to take a gfp_t argument.

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