Re: 2.6.21-mm1

Andrew Morton
2007-05-06T21:09:16Z

On Sun, 6 May 2007 22:57:32 +0200 Sam Ravnborg <sam@ravnborg.org> wrote:

> On Sun, May 06, 2007 at 02:49:49AM -0400, Valdis.Kletnieks@vt.edu wrote:
> > On Sat, 05 May 2007 01:49:55 PDT, Andrew Morton said:
> > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.21/2.6.21-mm1/
> >
> > MODPOST vmlinux
> > WARNING: mm/built-in.o - Section mismatch: reference to .init.text: from .text between 'kmem_cache_create' (at offset 0x20dff) and 'cache_reap'
> > WARNING: mm/built-in.o - Section mismatch: reference to .init.text: from .text between 'kmem_cache_create' (at offset 0x20e41) and 'cache_reap'
> >
> > Built with CONFIG_SLAB, CONFIG_SMP, x86_64.
>
> It comes from this code (mm/slab.c):
> /*
> * For setting up all the kmem_list3s for cache whose buffer_size is same as
> * size of kmem_list3.
> */
> static void __init set_up_list3s(struct kmem_cache *cachep, int index)
> {
> int node;
>
> for_each_online_node(node) {
> cachep->nodelists[node] = &initkmem_list3[index + node];
> cachep->nodelists[node]->next_reap = jiffies +
> REAPTIMEOUT_LIST3 +
> ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
> }
> }
>
> It is supposed to be used only during early init and thus marked __init.
> And initkmem_list3 is marked __initdata so that matches.
>
> But set_up_list3s() is used outside __init marked functions and thus result in an error.
>
> I do not know how to fix this.
>

Yes, this is one of those rare places which triggers a warning but where no
changes are needed.

I'm thinking that we could address this with a new section __nowarn and
__nowarndata (or whatever). These will have the same behaviour as regular
.text and .data, only the symbol-checking tool would know about them and
would suppress the warnings.

Perhaps there's some other way of communication this information from the C
level down into the checker - I haven't thought about it much.