[PATCH] add hook to read_from_oldmem() to check for non-ram pages

[Andrew Morton]

On Fri, 6 May 2011 21:39:16 +0200
Olaf Hering <olaf at 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.