From: glider@google.com
To: dvyukov@google.com, andreyknvl@google.com,
aryabinin@virtuozzo.com, akpm@linux-foundation.org
Cc: sergey.senozhatsky@gmail.com, arnd@arndb.de, linux-mm@kvack.org,
vegard.nossum@oracle.com, elver@google.com,
Alexander Potapenko <glider@google.com>
Subject: [PATCH 2/3] stackdepot: build with -fno-builtin
Date: Thu, 20 Feb 2020 15:19:15 +0100 [thread overview]
Message-ID: <20200220141916.55455-2-glider@google.com> (raw)
In-Reply-To: <20200220141916.55455-1-glider@google.com>
Clang may replace stackdepot_memcmp() with a call to instrumented bcmp(),
which is exactly what we wanted to avoid creating stackdepot_memcmp().
Building the file with -fno-builtin prevents such optimizations.
This patch has been previously mailed as part of KMSAN RFC patch series.
Signed-off-by: Alexander Potapenko <glider@google.com>
To: Alexander Potapenko <glider@google.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: linux-mm@kvack.org
---
lib/Makefile | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/lib/Makefile b/lib/Makefile
index 23ca78d43d247..390e90d2ee88b 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -220,6 +220,10 @@ obj-$(CONFIG_MEMREGION) += memregion.o
obj-$(CONFIG_STMP_DEVICE) += stmp_device.o
obj-$(CONFIG_IRQ_POLL) += irq_poll.o
+# stackdepot.c should not be instrumented or call instrumented functions.
+# Prevent the compiler from calling builtins like memcmp() or bcmp() from this
+# file.
+CFLAGS_stackdepot.o += -fno-builtin
obj-$(CONFIG_STACKDEPOT) += stackdepot.o
KASAN_SANITIZE_stackdepot.o := n
KCOV_INSTRUMENT_stackdepot.o := n
--
2.25.0.265.gbab2e86ba0-goog
next prev parent reply other threads:[~2020-02-20 14:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 14:19 [PATCH 1/3] stackdepot: check depot_index before accessing the stack slab glider
2020-02-20 14:19 ` glider [this message]
2020-02-20 14:19 ` [PATCH 3/3] kasan: stackdepot: move filter_irq_stacks() to stackdepot.c glider
2020-02-25 20:24 ` kbuild test robot
2020-02-26 9:53 ` Alexander Potapenko
2020-02-27 3:16 ` Greentime Hu
2020-03-07 13:37 ` Alexander Potapenko
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