Re: [PATCH v3 11/26] mm/swapfile: Annotate static information into meminspect

[Lorenzo Stoakes <ljs@kernel.org>]

On Thu, Jul 09, 2026 at 12:35:35AM +0530, Mukesh Ojha wrote:
> On Wed, Jul 08, 2026 at 08:47:51AM +0100, Lorenzo Stoakes wrote:
> > On Wed, Jul 08, 2026 at 11:01:50AM +0530, Mukesh Ojha wrote:
> > > From: Eugen Hristev <ehristev@kernel.org>
> > >
> > > Annotate vital static information into inspection table:
> > >  - nr_swapfiles
> > >
> > > Information on these variables is stored in a dedicated meminspect
> > > section.
> > >
> > > Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
> > > Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
> > > ---
> > >  mm/swapfile.c | 2 ++
> > >  1 file changed, 2 insertions(+)
> > >
> > > diff --git a/mm/swapfile.c b/mm/swapfile.c
> > > index a602e5820513..d480727e4987 100644
> > > --- a/mm/swapfile.c
> > > +++ b/mm/swapfile.c
> > > @@ -42,6 +42,7 @@
> > >  #include <linux/suspend.h>
> > >  #include <linux/zswap.h>
> > >  #include <linux/plist.h>
> > > +#include <linux/meminspect.h>
> > >
> > >  #include <asm/tlbflush.h>
> > >  #include <linux/leafops.h>
> > > @@ -65,6 +66,7 @@ static void move_cluster(struct swap_info_struct *si,
> > >   */
> > >  static DEFINE_SPINLOCK(swap_lock);
> > >  static unsigned int nr_swapfiles;
> > > +MEMINSPECT_SIMPLE_ENTRY(nr_swapfiles);
> >
> > Now the EXPORT_SYMBOL_GPL() is an EXPORT_SYMBOL() in effect no?
>
> The whole reason we had to tag most of the MM symbols is that
> the crash tool looks for this information while launching itself.

You're missing the point.

EXPORT_SYMBOL_GPL() != EXPORT_SYMBOL().

We cannot and will not allow symbols that are GPL-only to be exported by the
back door to non-GPL modules.

Meminspect seems to ignore all of this and just exports symbols another way
overriding kernel mechanisms which is just not acceptable...

I also don't really understand what you're saying here either, what has what
crash looks up on startup got to do with anything?

>
> e.g.,
>
> ./crash --no_modules --no_panic --no_kmem_cache --zero_excluded ./vmlinux  ./minidump.elf
>
>
> >
> > >  atomic_long_t nr_swap_pages;
> > >  /*
> > >   * Some modules use swappable objects and may try to swap them out under
> > >
> > > --
> > > 2.53.0
> > >
>
> --
> -Mukesh Ojha