The patch below does not apply to the 6.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y git checkout FETCH_HEAD git cherry-pick -x eded254cb69044bd4abde87394ea44909708d7c0 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2026010500-nutmeg-nacho-e072@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From eded254cb69044bd4abde87394ea44909708d7c0 Mon Sep 17 00:00:00 2001 From: SeongJae Park sj@kernel.org Date: Sat, 1 Nov 2025 11:20:02 -0700 Subject: [PATCH] mm/damon/tests/core-kunit: handle alloc failures on damon_test_split_regions_of()

damon_test_split_regions_of() is assuming all dynamic memory allocation in it will succeed. Those are indeed likely in the real use cases since those allocations are too small to fail, but theoretically those could fail. In the case, inappropriate memory access can happen. Fix it by appropriately cleanup pre-allocated memory and skip the execution of the remaining tests in the failure cases.

Link: https://lkml.kernel.org/r/20251101182021.74868-9-sj@kernel.org Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") Signed-off-by: SeongJae Park sj@kernel.org Cc: Brendan Higgins brendan.higgins@linux.dev Cc: David Gow davidgow@google.com Cc: Kefeng Wang wangkefeng.wang@huawei.com Cc: stable@vger.kernel.org [5.15+] Signed-off-by: Andrew Morton akpm@linux-foundation.org

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h index 98f2a3de7cea..10618cdd188e 100644 --- a/mm/damon/tests/core-kunit.h +++ b/mm/damon/tests/core-kunit.h @@ -278,15 +278,35 @@ static void damon_test_split_regions_of(struct kunit *test) struct damon_target *t; struct damon_region *r;

+ if (!c) + kunit_skip("ctx alloc fail"); t = damon_new_target(); + if (!t) { + damon_destroy_ctx(c); + kunit_skip(test, "target alloc fail"); + } r = damon_new_region(0, 22); + if (!r) { + damon_destroy_ctx(c); + damon_free_target(t); + kunit_skip(test, "region alloc fail"); + } damon_add_region(r, t); damon_split_regions_of(t, 2, DAMON_MIN_REGION); KUNIT_EXPECT_LE(test, damon_nr_regions(t), 2u); damon_free_target(t);

t = damon_new_target(); + if (!t) { + damon_destroy_ctx(c); + kunit_skip(test, "second target alloc fail"); + } r = damon_new_region(0, 220); + if (!r) { + damon_destroy_ctx(c); + damon_free_target(t); + kunit_skip(test, "second region alloc fail"); + } damon_add_region(r, t); damon_split_regions_of(t, 4, DAMON_MIN_REGION); KUNIT_EXPECT_LE(test, damon_nr_regions(t), 4u);