From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 795A541C2F2 for ; Mon, 13 Jul 2026 14:48:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783954085; cv=none; b=n1RUkFeVYKAN7s+YtsU6zW6ZJQLEpKIKQQ3VmDGJrScGsL+6686mLpZttqLrNg0bF+bIZL6t874RC2KSNdxxH8fiFQBudfUqMX5mb8laFbJuxRW9CoKx3aUNKHdg4sOg/WBOSXNczQQ0FRIELu6bnKnUYXHLkY3iXU9mte6EG0s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783954085; c=relaxed/simple; bh=0cY+TH2orxVeilb1agNyF3KgsT/Pz85auiOitqglEgo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=uKceQdE0yKYb31IcEyprnLQLKFSUN3Yz6tmoF/J8ly2uI0NH5rchQVk/eckAsmowU/iUJHWC5JPiQKTz2tBZjNHJ2FYrptZhyZn6T3g39cTX+z/xHT3nf+kL/ZnKV+tGuwMxa2BHEZXe9oBrh5WM+OxdTRZs4qJ8566urfsnFE8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cWays48u; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cWays48u" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ECA161F000E9; Mon, 13 Jul 2026 14:48:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783954084; bh=hBMk+fOlbJveogE5re7Nn/FoZf0Nt5Qg/hMm8UtTlqQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cWays48uss6rKi2IvsNsXOsLIVRKL6/+5hovBovlBDxHQSUlG7hm6FcXcazfjvS1I VkkC3R/eawR9fGyolV0NaaPB667l2G3WEjFFkz8EAM7hgZy5+kR2UyX3U2+EpSeXvG ZqZ67CpJkNu6phRsAwfnSzYmUKyL7ZJX6hGDEmH8SbcPjrR0trrnJqCIPiB1AxHhAP xdDxnTEq9gimCNIN+Xls6MN/jA8+VS1t9+35kvYWD0JrcL3pFAX/07WbHt2PemXA6f 8FODpmlV/WseKuYo8eVvU1CCjJYCfCvTKY/VU0hVs7Xh/TO9FkPuuCQrUkvttssRHC DbS5wn0CVPZ9Q== From: SJ Park To: sashiko-bot@kernel.org Cc: SJ Park , damon@lists.linux.dev Subject: Re: [RFC PATCH v1.2 2/5] mm/damon/tests/core-kunit: catch test failure in test_merge_regions_of() Date: Mon, 13 Jul 2026 07:47:55 -0700 Message-ID: <20260713144757.39740-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260713140806.D0CC61F00A3A@smtp.kernel.org> References: Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On Mon, 13 Jul 2026 14:08:06 +0000 sashiko-bot@kernel.org wrote: > Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: > > Pre-existing issues: > - [High] This problem wasn't introduced by this patch, but the fix is incomplete. The exact same vulnerability (NULL dereferences or out-of-bounds array accesses upon test expectation failure) exists in several other DAMON KUnit test functions. The patch correctly notes that `KUNIT_EXPECT_EQ()` does not abort execution, leading to NULL dereferences if subsequent code assumes the expectation was met. However, identical brittle patterns exist in `damon_do_test_apply_three_regions()` (which dereferences the result of `__nth_region_of()` without checking for NULL), `damos_test_commit_dests_for()` (which loops over `dst.nr_dests` and can dereference a `NULL` `src_node_id_arr`), and `damos_test_commit_quota_goals_for()` / `damon_test_commit_target_regions_for()` (which iterate based on the destination's size and can read out of bounds from the source arrays). > -- > > --- Patch [2]: [RFC PATCH v1.2 2/5] mm/damon/tests/core-kunit: catch test failure in test_merge_regions_of() --- > commit 5b98cb20c5802f828e4e3cf09a813b6c47d58774 > Author: SJ Park > > mm/damon/tests/core-kunit: catch test failure in test_merge_regions_of() > > 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. > > Link: https://lore.kernel.org/20260710144937.26981-1-sj@kernel.org > > > 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; > > [Severity: High] > This isn't a bug introduced by this patch, but does this fix need to be > applied to several other DAMON test functions that follow the same pattern? > > If a test expectation fails, these functions also assume the expectation > was met, which can lead to NULL pointer dereferences or stack out-of-bounds > reads. > > In mm/damon/tests/vaddr-kunit.h:damon_do_test_apply_three_regions(): > > for (i = 0; i < nr_expected / 2; i++) { > r = __nth_region_of(t, i); > KUNIT_EXPECT_EQ(test, r->ar.start, expected[i * 2]); > > If damon_set_regions() leaves fewer regions than expected, > __nth_region_of() returns NULL and r->ar.start dereferences it. > > In mm/damon/tests/core-kunit.h:damos_test_commit_dests_for(): > > for (i = 0; i < dst.nr_dests; i++) { > KUNIT_EXPECT_EQ(test, dst.node_id_arr[i], src_node_id_arr[i]); > > If dst.nr_dests is greater than src_nr_dests, it can access > src_node_id_arr[i] out of bounds (which can also be NULL). > > In mm/damon/tests/core-kunit.h:damos_test_commit_quota_goals_for(): > > damos_for_each_quota_goal(goal, (&dst)) { > KUNIT_EXPECT_EQ(test, goal->metric, src_goals[i].metric); > > This iterates over dst's goals without verifying against nr_src_goals, > potentially accessing the src_goals stack array out of bounds. > > In mm/damon/tests/core-kunit.h:damon_test_commit_target_regions_for(): > > damon_for_each_region(r, dst_target) { > KUNIT_EXPECT_EQ(test, r->ar.start, expect_start_end[i][0]); > > This blindly loops over dst_target's regions, leading to potential > out-of-bounds reads on expect_start_end if it exceeds nr_expect_regions. > > Could these functions be updated as well to prevent the test suite > from oopsing on expectation failures? I didn't check each one, but sounds right to me. I will further check and work on those later. > > > 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); > > } > > -- > Sashiko AI review ยท https://sashiko.dev/#/patchset/20260713135838.32730-1-sj@kernel.org?part=2 Thanks, SJ