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authorAlexander Potapenko <glider@google.com>2022-12-05 17:57:40 +0300
committerAndrew Morton <akpm@linux-foundation.org>2022-12-12 05:12:21 +0300
commit5478afc55a2104caaef5b78c7c1f9acb9ec1f92a (patch)
treed69444d2dd641b8f0006f7030c257a024e44deef /mm/kmsan
parentde2e5171433126d340573cb7d0d4fcac084ab2a0 (diff)
downloadlinux-5478afc55a2104caaef5b78c7c1f9acb9ec1f92a.tar.xz
kmsan: fix memcpy tests
Recent Clang changes may cause it to delete calls of memcpy(), if the source is an uninitialized volatile local. This happens because passing a pointer to a volatile local into memcpy() discards the volatile qualifier, giving the compiler a free hand to optimize the memcpy() call away. Use OPTIMIZER_HIDE_VAR() to hide the uninitialized var from the too-smart compiler. Link: https://lkml.kernel.org/r/20221205145740.694038-1-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Suggested-by: Marco Elver <elver@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/kmsan')
-rw-r--r--mm/kmsan/kmsan_test.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c
index 9a29ea2dbfb9..eb44ef3c5f29 100644
--- a/mm/kmsan/kmsan_test.c
+++ b/mm/kmsan/kmsan_test.c
@@ -419,6 +419,7 @@ static void test_memcpy_aligned_to_aligned(struct kunit *test)
kunit_info(
test,
"memcpy()ing aligned uninit src to aligned dst (UMR report)\n");
+ OPTIMIZER_HIDE_VAR(uninit_src);
memcpy((void *)&dst, (void *)&uninit_src, sizeof(uninit_src));
kmsan_check_memory((void *)&dst, sizeof(dst));
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
@@ -441,6 +442,7 @@ static void test_memcpy_aligned_to_unaligned(struct kunit *test)
kunit_info(
test,
"memcpy()ing aligned uninit src to unaligned dst (UMR report)\n");
+ OPTIMIZER_HIDE_VAR(uninit_src);
memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src));
kmsan_check_memory((void *)dst, 4);
KUNIT_EXPECT_TRUE(test, report_matches(&expect));
@@ -464,6 +466,7 @@ static void test_memcpy_aligned_to_unaligned2(struct kunit *test)
kunit_info(
test,
"memcpy()ing aligned uninit src to unaligned dst - part 2 (UMR report)\n");
+ OPTIMIZER_HIDE_VAR(uninit_src);
memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src));
kmsan_check_memory((void *)&dst[4], sizeof(uninit_src));
KUNIT_EXPECT_TRUE(test, report_matches(&expect));