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bh=SKLq7ZuoHq2BFm176pu4DfNEYfPU8F0EbpgzHa8ZXlA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mjT+7kGGAZYWj8JiuahXfYm2MBh7kCuE9DE+qZXwgVLnf66mD8V7l5743EVqT/ZB+ px2Kktm5XGebVXuPIEqzhuGDyAxeou/Yg5M3DlHa+j3Fh1/kpD0DD6txtSqp5RfQ/y lcFGHl2+XcewCNUxbjxgMnH9R0lVWko4XgbBORuqZ8AbCbSt3DFRDv8l8RRKBcrZQu 7eMhcaAEkzAYqX+zbo0qSI7Cf9AVEST+FwnpkEYdutt7uaJ2VpVjONtoiPhR2ZeCgT yXnTXCwj6RviPh1VazChP3DAGy28Q8nkBEV+kuYR+vDUeAfMfNytJrGMvgT14wTs20 D6KhmXJ2YEGMQ== 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 v1.1 2/5] mm/damon/tests/core-kunit: catch test failure in test_merge_regions_of() Date: Sun, 12 Jul 2026 10:03:24 -0700 Message-ID: <20260712170328.91144-3-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260712170328.91144-1-sj@kernel.org> References: <20260712170328.91144-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: A860D40005 X-Stat-Signature: wbu9d7n7hd59o5uhqxqzcayu419bj598 X-HE-Tag: 1783875820-590623 X-HE-Meta: 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 JV2nBgc3 nGhsa36KqauaYSInMdFcM/yPcGeha3s7qhakMUYsrHXbKibDWNBty9xK3QFHVKluJsLRyiMk9xcTXk9+fs9KS0kZ/qzK1VUldzSP4In0ul5eH2hqYwnkHzoHmMD6h4yskWX3dO0TQFl0smMT9uA4/wh4vU2Y/ggIqIruotSvWAYrF8klJoeKGrVg+irxJKr1TlxK4wnR9VxlxULh3NiK+Ts8ZEccUC79G3f7dyKqR7mHlLTYQxvJLI87eVn+xtFfXTAmWTt8yNsP+LJrBSNtoXrcXpeVwat924zH+PV0PGdcEZDVcqMKjSmcFVBauzsu03sOl 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