Re: [Patch 4/5] module: trim exception table in module_free()

[Amerigo Wang]

Rusty Russell wrote:
> On Thu, 4 Jun 2009 06:27:06 pm Amerigo Wang wrote:
>   
> > Rusty Russell wrote:
> >     
> > > I've taken this one to make it more generic.  I'll leave the x86
> > > maintainers to apply the rest.
> > >       
> > Thank you. But this one depends on the previous, I don't think you can
> > apply this without the previous ones.
> >     
>
> Here's what I ended up with: I need to rig up a test and make sure it goes to
> all the maintainers and linux-next.
>
> Subject: module: trim exception table on init free.
>
> It's theoretically possible that there are exception table entries
> which point into the (freed) init text of modules.  These could cause
> future problems if other modules get loaded into that memory and cause
> an exception as we'd see the wrong fixup.
>
> Amerigo fixed this long-standing FIXME in the x86 version, but this
> patch is more general.
>
> This implements trim_init_extable(); most archs are simple since they
> use the standard lib/extable.c sort code.  Alpha and IA64 use relative
> addresses in their fixups, so thier trimming is a slight variation.
>
> Sparc32 is unique; it doesn't seem to define ARCH_HAS_SORT_EXTABLE,
> yet it defines its own sort_extable() which overrides the one in lib.
> It doesn't sort, so we have to mark deleted entries instead of
> actually trimming them.
>
> Inspired-by: Amerigo Wang <amwang@xxxxxxxxxx>
> Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
>   

Very nice!
The generic part of this patch looks good for me, of course. :)

Thank you, Rusty!


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