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b=LQ/zMYiyDc9DBS+2PK4RjZYTpHzO2uSG2unKv5GwCgnDUqdMiXhJTqI0CAFZAa/3P 1VHFTEGSTxLynIIT943yFiCNPlZs2qYLlkPj5Lrfw3eveLRGKadq+v8/xT17JP2OpH L82xYFFVjkghxdfAMdHlpQzTJEh9RWCz2fVa3BBJsjN/WjDZR49JoYSQ71YyYsSRaF RDGRPLh6A1tTvWXaOQvf8hecqWIQ21JwhI3GXDDS4vJnPKRN/RLhDiRbTNbz5gq3Eq nd1bC5m5KLvePmsUtrEd19vJxmscIWClZ9+2ZPN9UuOnMDRbSCD/38I76b4JqnZrzo bKvk5Ooi9Yn2A== From: SJ Park To: Cc: SJ Park , stable@vger.kernel.org, Andrew Morton , Brendan Higgins , David Gow , SeongJae Park , damon@lists.linux.dev, kunit-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v1.2 2/5] mm/damon/tests/core-kunit: catch test failure in test_merge_regions_of() Date: Mon, 13 Jul 2026 06:58:33 -0700 Message-ID: <20260713135838.32730-3-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260713135838.32730-1-sj@kernel.org> References: <20260713135838.32730-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 7C75F40005 X-Stat-Signature: qqqsy7834iapfczywitm9dj7rue1977p X-HE-Tag: 1783951127-517621 X-HE-Meta: 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 drKSbNtk t5zDBrbWEAKqjBZ2BMHTTG1L6vvLGSdoa+BXWlUU9TzSCC2qVaIXD9GKiPUtq2005GJ5B7epmVxn7oweeA94xNMp05wU2bB9ZTo+yQI/I8rXf3+FyybJlbdb2DHte9xL112XRjeo+0bxNWu39cKJmmKw+Q+A21LsKTDppZDoaIhPMS8Jy0c8gwSz7008LApLUpdmJ7C6Jn8/W1YKOMI1VCM4TBHb2omvSX6VFk/Z659Qt/99FzTRAf8s7W27+mgEZS3Jm7zgX135f30c3gkaCTW5als3750CpcuQUJtLntfnps7RvQYiiYru783ISUqAObXXp Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: KUNIT_EXPECT_EQ() does not abort the execution of test code when the expectation is not met. But damon_test_merge_regions_of() code after its initial KUNIT_EXPECT_EQ() call assumes the expectation is met. It does a per-region test with a hard-coded number of regions that is correct only if the expectation was met. As a result, __nth_region_of() could return NULL, and the test code can dereference NULL pointers. Fix the issue by catching the expectation failure and skip the per-region tests. The user impact on realistic setups should be negligible, as it is a unit test. The issue was discovered [1] by Sashiko. [1] https://lore.kernel.org/20260710144937.26981-1-sj@kernel.org Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") Cc: # 5.15.x Signed-off-by: SJ Park --- mm/damon/tests/core-kunit.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h index 6ad73559dd8ea..a99363720e677 100644 --- a/mm/damon/tests/core-kunit.h +++ b/mm/damon/tests/core-kunit.h @@ -260,11 +260,14 @@ static void damon_test_merge_regions_of(struct kunit *test) damon_merge_regions_of(t, 9, 9999, ctx); /* 0-112, 114-130, 130-156, 156-170, 170-230, 230-10170 */ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 6u); + if (damon_nr_regions(t) != 6) + goto out; for (i = 0; i < 6; i++) { r = __nth_region_of(t, i); KUNIT_EXPECT_EQ(test, r->ar.start, saddrs[i]); KUNIT_EXPECT_EQ(test, r->ar.end, eaddrs[i]); } +out: damon_free_target(t); damon_destroy_ctx(ctx); } -- 2.47.3