Date: Fri, 6 May 2011 12:55:46 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Olaf Hering <olaf@aepfle.de>
Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org
Subject: Re: [PATCH] add hook to read_from_oldmem() to check for non-ram
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On Fri, 6 May 2011 21:39:16 +0200
Olaf Hering <olaf@aepfle.de> wrote:

> On Fri, May 06, Andrew Morton wrote:
> 
> > So as your module will have a reference to vmcore.c's register and unregister
> > functions, nothing needs to be done: the presence of the client module alone
> > will pin the vmcore.c module.
> 
> I meant the other way around. Keep /proc/vmcore open and read from it,
> then try to rmmod foo.ko which provides fn().
> 

The client foo.ko will need to prevent itself from being unloaded while
it's actively doing stuff, yes.  Typically that would be done in its
module_exit() function - wait for current activity to complete and
block new activity.  The "block new activity" thing should be automatic
because nobody has any more references to anything in the module.

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