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| author | Alexander Potapenko <glider@google.com> | 2022-12-05 15:57:40 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-12-11 18:12:21 -0800 |
| commit | 5478afc55a2104caaef5b78c7c1f9acb9ec1f92a (patch) | |
| tree | d69444d2dd641b8f0006f7030c257a024e44deef /mm | |
| parent | de2e5171433126d340573cb7d0d4fcac084ab2a0 (diff) | |
| download | lwn-5478afc55a2104caaef5b78c7c1f9acb9ec1f92a.tar.gz lwn-5478afc55a2104caaef5b78c7c1f9acb9ec1f92a.zip | |
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')
| -rw-r--r-- | mm/kmsan/kmsan_test.c | 3 |
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)); |