kselftest: vm: fix tabs/spaces inconsistency in the mdwe test

kselftest: vm: fix tabs/spaces inconsistency in the mdwe test

Patch series "MDWE without inheritance", v4.

Joey recently introduced a Memory-Deny-Write-Executable (MDWE) prctl which
tags current with a flag that prevents pages that were previously not
executable from becoming executable.  This tag always gets inherited by
children tasks.  (it's in MMF_INIT_MASK)

At Google, we've been using a somewhat similar downstream patch for a few
years now.  To make the adoption of this feature easier, we've had it
support a mode in which the W^X flag does not propagate to children.  For
example, this is handy if a C process which wants W^X protection suspects
it could start children processes that would use a JIT.

I'd like to align our features with the upstream prctl.  This series
proposes a new NO_INHERIT flag to the MDWE prctl to make this kind of
adoption easier.  It sets a different flag in current that is not in
MMF_INIT_MASK and which does not propagate.

As part of looking into MDWE, I also fixed a couple of things in the MDWE
test.

The background for this was discussed in these threads:
v1: https://lore.kernel.org/all/66900d0ad42797a55259061f757beece@ispras.ru/
v2: https://lore.kernel.org/all/d7e3749c-a718-df94-92af-1cb0fecab772@redhat.com/

This patch (of 6):

Fix tabs/spaces inconsistency in the mdwe test.

Link: https://lkml.kernel.org/r/20230828150858.393570-1-revest@chromium.org
Link: https://lkml.kernel.org/r/20230828150858.393570-2-revest@chromium.org
Signed-off-by: Florent Revest <revest@chromium.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexey Izbyshev <izbyshev@ispras.ru>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ayush Jain <ayush.jain3@amd.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Szabolcs Nagy <Szabolcs.Nagy@arm.com>
Cc: Topi Miettinen <toiwoton@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>