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bh=pbj4M0PCAFhChb2r0bNN0cHfe6XonAYY07ZTVFUWh04=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=NlR9W1Qcz8xV7IqYh9TId8gWx/a84Z1oJt38FZGx/ZhwBtOZqmdUG6YY/SGybTLvO +QOkqHi6KptogQW+p04qBCVT9NPA0K6Jcq1iXiT7XsoVhiiDqhnqtGWkbzhczFVbTL nlilupHYRytu7Ms8aO7Ixi2kJgGhoKHLIheM+zE09nWqJRBSLcilBKDrHnmjKFkku8 zj/O+mYJl6D11ahUh871RSWcAMMERFrh0N+7s8K/CpCshntF3sgJM4eZxueJTlSkUM EAlEqDPphJYMdRFGCt4QJp1/v/tqqjByAck20wRZRkf90wzCGzY3eg2EpKraSriHWX Xf2nccWV8oHOQ== From: SJ Park To: Cc: SJ Park , "# 5 . 15 . x" , 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 2/5] mm/damon/tests/core-kunit: catch test failure in test_merge_regions_of() Date: Sat, 11 Jul 2026 11:04:05 -0700 Message-ID: <20260711180409.82093-3-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260711180409.82093-1-sj@kernel.org> References: <20260711180409.82093-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 8665420009 X-Stat-Signature: na8n73dk5wgt1i3x5r3a7kyxfb4x3fas X-HE-Tag: 1783793061-609150 X-HE-Meta: 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 y/Anm0Si 4BP7CplUI6Vp6OPSZcpDyqCGxH1cJ1RtAIkyALAe1g5ETqLd9l/+XvxmBTZaTbTo4h+Ce1cmdldLoF6PlPFBg5MObfQWOJ8Dc1fPcAxKNug022S/ylFoCKOvdcS8toO0qPqUOxv/OqpYjjFjPnthAknv2emqFxG6ZU61P8MdJgfCtkSeqeNrBJ+hUXd1kv7SqooCFyyDZqpLpFKNeV66CccAiPU9AhY6nTbmNCvQ6tzwMwsVm8MWi5Ie0FSGSL6gRbWHrAuLEbe565oFC+mWX6ATXdUSPJ7Yu++3EHJOh52GbQsfR3jfowp2aRXeLgdA6J4d/ 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 68d30648c612e..fb882a0602ff9 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, true); /* 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