FAILED: patch "[PATCH] mm/damon/tests/core-kunit: handle alloc failures on" failed to apply to 6.18-stable tree

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 <[email protected]>.

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 '<[email protected]>' --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 <[email protected]>
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.

index 98f2a3de7cea..10618cdd188e 100644
@@ -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);

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.

---
 mm/damon/tests/core-kunit.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

index 51369e35298b..000b11f891fe 100644
@@ -227,15 +227,35 @@ static void damon_test_split_regions_of(struct kunit *test)
 	struct damon_target *t;
 	struct damon_region *r;
 
+	if (!c)
+		kunit_skip(test, "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);

2.47.3

This is a note to let you know that I've just added the patch titled

mm/damon/tests/core-kunit: handle alloc failures on damon_test_split_regions_of()

to the 6.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mm-damon-tests-core-kunit-handle-alloc-failures-on-damon_test_split_regions_of.patch
and it can be found in the queue-6.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From [email protected] Tue Jan 6 02:55:58 2026
From: SeongJae Park <[email protected]>
Date: Mon, 5 Jan 2026 17:42:49 -0800
Subject: mm/damon/tests/core-kunit: handle alloc failures on damon_test_split_regions_of()
To: [email protected]
Cc: [email protected], SeongJae Park <[email protected]>, Brendan Higgins <[email protected]>, David Gow <[email protected]>, Kefeng Wang <[email protected]>, Andrew Morton <[email protected]>
Message-ID: <[email protected]>

From: SeongJae Park <[email protected]>

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.

---
 mm/damon/tests/core-kunit.h |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

@@ -278,15 +278,35 @@ static void damon_test_split_regions_of(
 	struct damon_target *t;
 	struct damon_region *r;
 
+	if (!c)
+		kunit_skip(test, "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);

Patches currently in stable-queue which might be from [email protected] are

queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failures-on-dasmon_test_merge_regions_of.patch queue-6.18/mm-damon-tests-vaddr-kunit-handle-alloc-failures-on-damon_do_test_apply_three_regions.patch queue-6.18/mm-damon-tests-core-kunit-handle-memory-failure-from-damon_test_target.patch queue-6.18/mm-damon-tests-core-kunit-handle-allocation-failures-in-damon_test_regions.patch queue-6.18/mm-damon-tests-core-kunit-fix-memory-leak-in-damon_test_set_filters_default_reject.patch queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failures-on-damos_test_filter_out.patch queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failures-on-damon_test_split_at.patch queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failres-in-damon_test_new_filter.patch queue-6.18/mm-damon-tests-vaddr-kunit-handle-alloc-failures-in-damon_test_split_evenly_fail.patch queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failures-on-damon_test_set_filters_default_reject.patch queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failures-in-damon_test_set_regions.patch queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failures-on-damon_test_split_regions_of.patch queue-6.18/mm-damon-tests-core-kunit-handle-memory-alloc-failure-from-damon_test_aggregate.patch queue-6.18/mm-damon-tests-vaddr-kunit-handle-alloc-failures-on-damon_test_split_evenly_succ.patch queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failure-on-damon_test_set_attrs.patch queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failure-on-damos_test_commit_filter.patch queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failures-in-damon_test_ops_registration.patch queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failures-on-damon_test_merge_two.patch queue-6.18/mm-damon-tests-sysfs-kunit-handle-alloc-failures-on-damon_sysfs_test_add_targets.patch queue-6.18/mm-damon-tests-core-kunit-handle-alloc-failures-in-damon_test_update_monitoring_result.patch