On Tue, Jan 07, 2020 at 11:11:07PM +0000, Andrew Morton wrote:
> On Mon, 6 Jan 2020 17:07:44 +1100 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> > Hi all,
> >
> > After merging the akpm tree, today's linux-next build (x86_64
> > allmodconfig) produced this warning:
> >
> > arch/x86/mm/dump_pagetables.c: In function 'ptdump_walk_pgd_level_core':
> > arch/x86/mm/dump_pagetables.c:403:1: warning: the frame size of 2128 bytes is larger than 2048 bytes [-Wframe-larger-than=]
> > 403 | }
> > | ^
> >
> > Introduced by commit
> >
> > 710fae4f03f2 ("x86: mm: convert dump_pagetables to use walk_page_range")
> >
>
> (gdb) p sizeof(struct mm_struct)
> $1 = 1664
>
> yup, that'll do it.
Ok, looks like I'll have to do something a little bit more clever than
the "fake_mm" hack I used before. The trouble is x86 now has two PGDs
due to the PAGE_TABLE_ISOLATION feature. I was trying to isolate this
quirk to the x86 code, but it looks like we need some way of passing an
"override" down for the PGD.
I'll post a possible fix as a reply to this post.
Steve
