From: Jann Horn <jannh@google.com>
To: Marco Elver <elver@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nicolas Schier <nicolas.schier@linux.dev>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Lameter <cl@gentwo.org>,
David Rientjes <rientjes@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
Roman Gushchin <roman.gushchin@linux.dev>,
Harry Yoo <harry.yoo@oracle.com>,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
kasan-dev@googlegroups.com, linux-mm@kvack.org
Subject: Re: [PATCH early RFC 2/4] kbuild: kasan: refactor open coded cflags for kasan test
Date: Tue, 5 Aug 2025 15:49:45 +0200 [thread overview]
Message-ID: <CAG48ez2_HrKjRuH+5KSB+vK_9dGeNnh2O6qAN0ePr4BRnt3xzw@mail.gmail.com> (raw)
In-Reply-To: <CANpmjNOJxJ+kM4J7O5J8meSD_V=4uAa6SwFCiG83Vv_8kn56sw@mail.gmail.com>
On Tue, Aug 5, 2025 at 2:31 PM Marco Elver <elver@google.com> wrote:
> On Mon, 4 Aug 2025 at 21:18, Jann Horn <jannh@google.com> wrote:
> > In the Makefile for mm/kasan/, KASAN is broadly disabled to prevent the
> > KASAN runtime from recursing into itself; but the KASAN tests must be
> > exempt from that.
> >
> > This is currently implemented by duplicating the same logic that is also
> > in scripts/Makefile.lib. In preparation for changing that logic,
> > refactor away the duplicate logic - we already have infrastructure for
> > opting in specific files inside directories that are opted out.
> >
> > Signed-off-by: Jann Horn <jannh@google.com>
> > ---
> > mm/kasan/Makefile | 12 ++----------
> > 1 file changed, 2 insertions(+), 10 deletions(-)
> >
> > diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
> > index dd93ae8a6beb..922b2e6f6d14 100644
> > --- a/mm/kasan/Makefile
> > +++ b/mm/kasan/Makefile
> > @@ -35,18 +35,10 @@ CFLAGS_shadow.o := $(CC_FLAGS_KASAN_RUNTIME)
> > CFLAGS_hw_tags.o := $(CC_FLAGS_KASAN_RUNTIME)
> > CFLAGS_sw_tags.o := $(CC_FLAGS_KASAN_RUNTIME)
> >
> > -CFLAGS_KASAN_TEST := $(CFLAGS_KASAN)
> > -ifndef CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX
> > -# If compiler instruments memintrinsics by prefixing them with __asan/__hwasan,
> > -# we need to treat them normally (as builtins), otherwise the compiler won't
> > -# recognize them as instrumentable. If it doesn't instrument them, we need to
> > -# pass -fno-builtin, so the compiler doesn't inline them.
> > -CFLAGS_KASAN_TEST += -fno-builtin
>
> Has the -fno-builtin passed to test if
> !CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX become redundant?
... oh, bleh, good catch. Somehow I had convinced myself that
scripts/Makefile.kasan did this, but no, that only sets -fno-builtin
for uninstrumented code... I misunderstood what was going on here.
next prev parent reply other threads:[~2025-08-05 13:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-04 19:17 [PATCH early RFC 0/4] running KASAN off of KCSAN's TSAN hooks Jann Horn
2025-08-04 19:17 ` [PATCH early RFC 1/4] kbuild: kasan,kcsan: refactor out enablement check Jann Horn
2025-08-04 19:17 ` [PATCH early RFC 2/4] kbuild: kasan: refactor open coded cflags for kasan test Jann Horn
2025-08-05 12:30 ` Marco Elver
2025-08-05 13:49 ` Jann Horn [this message]
2025-08-04 19:17 ` [PATCH early RFC 3/4] kasan: add support for running via KCSAN hooks Jann Horn
2025-08-04 19:17 ` [PATCH early RFC 4/4] mm/slub: Defer KCSAN hook on free to KASAN if available Jann Horn
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAG48ez2_HrKjRuH+5KSB+vK_9dGeNnh2O6qAN0ePr4BRnt3xzw@mail.gmail.com \
--to=jannh@google.com \
--cc=akpm@linux-foundation.org \
--cc=andreyknvl@gmail.com \
--cc=cl@gentwo.org \
--cc=dvyukov@google.com \
--cc=elver@google.com \
--cc=glider@google.com \
--cc=harry.yoo@oracle.com \
--cc=kasan-dev@googlegroups.com \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=masahiroy@kernel.org \
--cc=nathan@kernel.org \
--cc=nicolas.schier@linux.dev \
--cc=rientjes@google.com \
--cc=roman.gushchin@linux.dev \
--cc=ryabinin.a.a@gmail.com \
--cc=vbabka@suse.cz \
--cc=vincenzo.frascino@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).