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

Andrew Morton
2011-05-06T19:55:54Z

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.