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b=CfAbMLTf558lsnXavsBfIowovwZYqHiUt4jX3iHP9sYrYd8xvWyRsvrpSvw0MSTWY nTcbokmih6UEEtk7TKjAgq6PEtBt7VusLCyE6/gkskuqKzlKEPlo6tHYl6nQ1TAkVa j+Srwx13jxoE3PzjlTZiqIb2fplrrza5feZkxkcAMJ9HLGRwnHSzv/5XpJPGIf8vRA 6sP2WNThsPfP5+a28TQJ9obpiIl6Zkye1TLUF3f/2wVAmTBrMqaDmdGjTKt0AqbSkx 97tj/l2r23MalKc/ingRhKlRlXWkRW1pjllfd7rXyMGpOatQYwoI+Yo4upeXu0ROJX SrEmPADQFTI7g== From: SJ Park To: Cc: SJ Park , stable@vger.kernel.org, Andrew Morton , Brendan Higgins , David Gow , damon@lists.linux.dev, kunit-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 4/7] mm/damon/core-kunit: handle region split failure in filter_out() Date: Thu, 16 Jul 2026 17:30:18 -0700 Message-ID: <20260717003022.119437-5-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260717003022.119437-1-sj@kernel.org> References: <20260717003022.119437-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 53ED8A0004 X-Stat-Signature: 7ra4sz8wz6qhuwjspym3ag9h5sqxdrq6 X-Rspam-User: X-HE-Tag: 1784248234-366601 X-HE-Meta: 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 JRB+nWR2 reKSpu5cXuEOpEmcE8DWfE9bVdBb+12cAvi1UjS5EX60QmdcHd+cKwlx7w4KrtfDQra9VxwoEMUKB/yHOUaK64+McuLP4kXDDUYtzZvyeuhfgfrK1CF5XIKXkPxxtvnbAg+8ZBWkk2+tayh+wsUUtwiVCv6UxYf5PxGvXpsZg9fntrtF+qAFs5ELT9DjuBHTRi3mWsyxQ0kXUsuVA51cRwgWqI4ozYkeNOxQLF/ij7D85dYebAcpLPrNzHIn9QrdQjaQw/RBN42BBca2hLFHKdg1zNg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: dasmon_test_filter_out() test checks if damos_filter_match() of an address filter splits the region as expected under a given condition. But, the test continued regardless of the split successes. As a result, the later part of the test could dereference invalid pointers that returned from damon_next_region(). Further, it could corrupt memory from damon_destroy_region(). The consequent user impact (memory corruption) is quite bad. The realistic user impact would be limited, though. It would affect only test run setups. Fix it by exiting early for the number of regions test failure. The issue was discovered [1] by Sashiko. [1] https://lore.kernel.org/20260714142352.100478-1-sj@kernel.org Fixes: 26713c890875 ("mm/damon/core-test: add a unit test for __damos_filter_out()") Cc: # 6.6.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 322a295ac2cec..bd3bbd421392f 100644 --- a/mm/damon/tests/core-kunit.h +++ b/mm/damon/tests/core-kunit.h @@ -1365,6 +1365,8 @@ static void damos_test_filter_out(struct kunit *test) KUNIT_EXPECT_EQ(test, r->ar.start, 1); KUNIT_EXPECT_EQ(test, r->ar.end, 2); KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 2); + if (damon_nr_regions(t) != 2) + goto out; r2 = damon_next_region(r); KUNIT_EXPECT_EQ(test, r2->ar.start, 2); KUNIT_EXPECT_EQ(test, r2->ar.end, 4); @@ -1384,6 +1386,7 @@ static void damos_test_filter_out(struct kunit *test) KUNIT_EXPECT_EQ(test, r2->ar.end, 8); damon_destroy_region(r2, t); +out: damon_free_target(t); damos_free_filter(f); } -- 2.47.3