From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: kasan: prevent compiler from optimizing away memset in tests A compiler can optimize away memset calls by replacing them with mov instructions. There are KASAN tests that specifically test that KASAN correctly handles memset calls so we don't want this optimization to happen. The solution is to add -fno-builtin flag to test_kasan.ko Link: http://lkml.kernel.org/r/105ec9a308b2abedb1a0d1fdced0c22d765e4732.1519924383.git.andreyknvl@xxxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Acked-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Cc: Nick Terrell <terrelln@xxxxxx> Cc: Chris Mason <clm@xxxxxx> Cc: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: "Luis R . Rodriguez" <mcgrof@xxxxxxxxxx> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx> Cc: "Paul E . McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> Cc: Jeff Layton <jlayton@xxxxxxxxxx> Cc: "Jason A . Donenfeld" <Jason@xxxxxxxxx> Cc: Kostya Serebryany <kcc@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/Makefile | 1 + 1 file changed, 1 insertion(+) diff -puN lib/Makefile~kasan-disallow-compiler-to-optimize-away-memset-in-tests lib/Makefile --- a/lib/Makefile~kasan-disallow-compiler-to-optimize-away-memset-in-tests +++ a/lib/Makefile @@ -53,6 +53,7 @@ obj-$(CONFIG_TEST_FIRMWARE) += test_firm obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o obj-$(CONFIG_TEST_KASAN) += test_kasan.o +CFLAGS_test_kasan.o += -fno-builtin obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o obj-$(CONFIG_TEST_LIST_SORT) += test_list_sort.o obj-$(CONFIG_TEST_LKM) += test_module.o _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
