+ mm-damon-sysfs-dealloc-repeat_call_control-if-damon_call-fails.patch added to mm-hotfixes-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/damon/sysfs: dealloc repeat_call_control if damon_call() fails
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-damon-sysfs-dealloc-repeat_call_control-if-damon_call-fails.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-sysfs-dealloc-repeat_call_control-if-damon_call-fails.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: SeongJae Park <sj@kernel.org>
Subject: mm/damon/sysfs: dealloc repeat_call_control if damon_call() fails
Date: Thu, 26 Mar 2026 17:32:22 -0700

damon_call() for repeat_call_control of DAMON_SYSFS could fail if somehow
the kdamond is stopped before the damon_call().  It could happen, for
example, when te damon context was made for monitroing of a virtual
address processes, and the process is terminated immediately, before the
damon_call() invocation.  In the case, the dyanmically allocated
repeat_call_control is not deallocated and leaked.

Fix the leak by deallocating the repeat_call_control under the
damon_call() failure.

This issue is discovered by sashiko [1].

Link: https://lkml.kernel.org/r/20260327003224.55752-1-sj@kernel.org
Link: https://lore.kernel.org/20260320020630.962-1-sj@kernel.org [1]
Fixes: 04a06b139ec0 ("mm/damon/sysfs: use dynamically allocated repeat mode damon_call_control")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[6.17+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/damon/sysfs.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/damon/sysfs.c~mm-damon-sysfs-dealloc-repeat_call_control-if-damon_call-fails
+++ a/mm/damon/sysfs.c
@@ -1670,7 +1670,8 @@ static int damon_sysfs_turn_damon_on(str
 	repeat_call_control->data = kdamond;
 	repeat_call_control->repeat = true;
 	repeat_call_control->dealloc_on_cancel = true;
-	damon_call(ctx, repeat_call_control);
+	if (damon_call(ctx, repeat_call_control))
+		kfree(repeat_call_control);
 	return err;
 }
 
_

Patches currently in -mm which might be from sj@kernel.org are

mm-damon-sysfs-dealloc-repeat_call_control-if-damon_call-fails.patch
mm-damon-add-config_damon_debug_sanity.patch
mm-damon-core-add-damon_new_region-debug_sanity-check.patch
mm-damon-core-add-damon_del_region-debug_sanity-check.patch
mm-damon-core-add-damon_nr_regions-debug_sanity-check.patch
mm-damon-core-add-damon_merge_two_regions-debug_sanity-check.patch
mm-damon-core-add-damon_merge_regions_of-debug_sanity-check.patch
mm-damon-core-add-damon_split_region_at-debug_sanity-check.patch
mm-damon-core-add-damon_reset_aggregated-debug_sanity-check.patch
mm-damon-tests-kunitconifg-enable-damon_debug_sanity.patch
selftests-damon-config-enable-damon_debug_sanity.patch
mm-damon-tests-core-kunit-add-a-test-for-damon_commit_ctx.patch
docs-mm-damon-design-document-the-power-of-two-limitation-for-addr_unit.patch
mm-damon-core-remove-damos_set_next_apply_sis-duplicates.patch
mm-damon-core-use-time_before-for-next_apply_sis.patch
mm-damon-core-use-time_after_eq-in-kdamond_fn.patch
mm-damon-core-use-mult_frac.patch
mm-damon-tests-core-kunit-add-a-test-for-damon_is_last_region.patch
mm-damon-core-clarify-damon_set_attrs-usages.patch
mm-damon-document-non-zero-length-damon_region-assumption.patch
docs-admin-guide-mm-damn-lru_sort-fix-intervals-autotune-parameter-name.patch
docs-mm-damon-maintainer-profile-use-flexible-review-cadence.patch
docs-mm-damon-index-fix-typo-autoamted-automated.patch
mm-damon-core-introduce-damos_quota_goal_tuner.patch
mm-damon-core-allow-quota-goals-set-zero-effective-size-quota.patch
mm-damon-core-introduce-damos_quota_goal_tuner_temporal.patch
mm-damon-sysfs-schemes-implement-quotas-goal_tuner-file.patch
docs-mm-damon-design-document-the-goal-based-quota-tuner-selections.patch
docs-admin-guide-mm-damon-usage-document-goal_tuner-sysfs-file.patch
docs-abi-damon-update-for-goal_tuner.patch
mm-damon-tests-core-kunit-test-goal_tuner-commit.patch
selftests-damon-_damon_sysfs-support-goal_tuner-setup.patch
selftests-damon-drgn_dump_damon_status-support-quota-goal_tuner-dumping.patch
selftests-damon-sysfspy-test-goal_tuner-commit.patch
mm-damon-core-fix-wrong-end-address-assignment-on-walk_system_ram.patch
mm-damon-core-support-addr_unit-on-damon_find_biggest_system_ram.patch
mm-damon-core-receive-addr_unit-on-damon_set_region_biggest_system_ram_default.patch
mm-damon-core-receive-addr_unit-on-damon_set_region_biggest_system_ram_default-fix.patch
mm-damon-reclaim-respect-addr_unit-on-default-monitoring-region-setup.patch
mm-damon-lru_sort-respect-addr_unit-on-default-monitoring-region-setup.patch