+ mm-damon-core-wait-ctx-stop-in-damon_call-before-reruning-an-error.patch added to mm-new branch

+ mm-damon-core-wait-ctx-stop-in-damon_call-before-reruning-an-error.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/damon/core: wait ctx stop in damon_call() before reruning an error
has been added to the -mm mm-new branch.  Its filename is
     mm-damon-core-wait-ctx-stop-in-damon_call-before-reruning-an-error.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-core-wait-ctx-stop-in-damon_call-before-reruning-an-error.patch

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

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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and is updated there most days

------------------------------------------------------
From: SJ Park <sj@kernel.org>
Subject: mm/damon/core: wait ctx stop in damon_call() before reruning an error
Date: Mon, 6 Jul 2026 07:06:24 -0700

damon_call() failure means the DAMON context started its termination.  The
termination is asynchronously done in kdamond thread.  The caller's error
handling should handle the race, too.  It is complicated and easy to make
mistakes.

Update damon_call() to ensure the context is stopped in the case, by
waiting until the completion is confirmed.

Link: https://lore.kernel.org/20260706140628.87414-10-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/damon/core.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--- a/mm/damon/core.c~mm-damon-core-wait-ctx-stop-in-damon_call-before-reruning-an-error
+++ a/mm/damon/core.c
@@ -2010,6 +2010,8 @@ int damon_kdamond_pid(struct damon_ctx *
  * @ctx has succeeded.  Otherwise, this function could fall into an indefinite
  * wait.
  *
+ * When this function is failed, the @ctx is guaranteed to be stopped.
+ *
  * Return: 0 on success, negative error code otherwise.
  */
 int damon_call(struct damon_ctx *ctx, struct damon_call_control *control)
@@ -2022,7 +2024,7 @@ int damon_call(struct damon_ctx *ctx, st
 	mutex_lock(&ctx->call_controls_lock);
 	if (ctx->call_controls_obsolete) {
 		mutex_unlock(&ctx->call_controls_lock);
-		return -ECANCELED;
+		goto canceled;
 	}
 	list_add_tail(&control->list, &ctx->call_controls);
 	mutex_unlock(&ctx->call_controls_lock);
@@ -2030,8 +2032,14 @@ int damon_call(struct damon_ctx *ctx, st
 		return 0;
 	wait_for_completion(&control->completion);
 	if (control->canceled)
-		return -ECANCELED;
+		goto canceled;
 	return 0;
+
+canceled:
+	while (damon_is_running(ctx))
+		schedule_timeout_idle(msecs_to_jiffies(100));
+	return -ECANCELED;
+
 }
 
 /**
_

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

maintainers-s-seongjae-sj.patch
mm-damon-core-validate-ranges-in-damon_set_regions.patch
mm-damon-core-disallow-overlapping-input-ranges-for-damon_set_regions.patch
samples-damon-wsse-handle-damon_start-failure.patch
samples-damon-prcl-handle-damon_start-failure.patch
samples-damon-mtier-handle-damon_start-failure.patch
samples-damon-mtier-handle-damon_stop-failure.patch
samples-damon-wsse-stop-and-free-damon-ctx-when-damon_call-fails.patch
samples-damon-prcl-stop-and-free-damon-ctx-when-damon_call-fails.patch
mm-damon-sysfs-kobject_del-target-normal-context-and-kdamond-dirs.patch
mm-damon-sysfs-kobject_del-region-and-target-error-dirs.patch
mm-damon-sysfs-schemes-kobject_del-scheme-dirs.patch
mm-damon-sysfs-schemes-kobject_del-scheme-region-dirs.patch
mm-damon-sysfs-schemes-kobject_del-scheme-filter-dirs.patch
mm-damon-sysfs-schemes-kobject_del-scheme-quota-goal-dirs.patch
mm-damon-sysfs-schemes-kobject_del-scheme-action-destination-dirs.patch
mm-damon-sysfs-kobject_del-probe-dirs.patch
mm-damon-sysfs-kobject_del-probe-filter-dirs.patch
mm-damon-sysfs-kobject_del-probe-dirs-in-probes_addd_dir-error-path.patch
mm-damon-sysfs-schemes-kobject_del-region-for-populate_region-error.patch
docs-mm-damon-design-update-for-damos_quota_node_eligible_mem_bp.patch
docs-abi-damon-document-probe-files.patch
mm-damon-tests-core-kunit-test-damon_rand.patch
selftests-damon-sysfssh-test-multiple-probe-dirs-creation.patch
selftests-damon-sysfssh-test-coreops_filters-directories.patch
selftests-damon-sysfssh-test-dests-dir.patch
selftests-damon-sysfssh-test-all-files-in-quota-goal-dir.patch
mm-damon-core-reduce-range-setup-in-damon_commit_target_regions.patch
mm-damon-sysfs-split-probe-setup-function-out.patch
mm-damon-sysfs-split-out-filters-setup-function.patch
mm-damon-sysfs-fix-typos-in-probe_addrm_dirs-s-attr-probe.patch
mm-damon-core-introduce-damon_nr_accesses_mvsum.patch
mm-damon-tests-core-kunit-test-damon_mvsum.patch
mm-damon-core-always-update-last_nr_accesses-for-intervals-change.patch
mm-damon-core-handle-unreset-nr_accesses-in-damon_nr_accesses_mvsum.patch
mm-damon-core-use-damon_nr_accesses_mvsum-in-__damos_valid_target.patch
mm-damon-core-use-damon_nr_accesses_mvsum-for-damos-region-tracing.patch
mm-damon-sysfs-schemes-use-damon_nr_accesses_mvsum-for-damo-regions.patch
mm-damon-core-remove-damon_warn_fix_nr_accesses_corruption.patch
mm-damon-core-remove-damon_verify_reset_aggregated.patch
mm-damon-core-remove-damon_verify_merge_regions_of.patch
mm-damon-tests-core-kunit-remove-nr_accesses_bp-setup-and-tests.patch
selftests-damon-drgn_dump_damon_status-do-not-dump-nr_accesses_bp.patch
mm-damon-core-remove-nr_accesses_bp-setups-and-updates.patch
mm-damon-core-remove-attrs-param-from-damon_update_region_access_rate.patch
mm-damon-paddr-remove-attrs-param-from-__damon_pa_check_access.patch
mm-damon-vaddr-remove-attrs-param-from-__damon_va_check_access.patch
mm-damon-core-remove-damon_moving_sum-and-its-unit-test.patch
mm-damon-core-remove-damon_region-nr_accesses_bp.patch
mm-damon-add-damon_region-last_probe_hits.patch
mm-damon-core-introduce-damon_probe_hits_mvsum.patch
mm-damon-sysfs-schemes-set-probe-hits-as-pseudo-moving-sums.patch
mm-damon-core-safely-validate-src-on-damon_commit_ctx.patch
mm-damon-core-do-parameter-testing-commit-on-damon_start.patch
mm-damon-sysfs-remove-duplicated-commit-input-validity-check.patch
mm-damon-reclaim-remove-duplicated-min_region_sz-power-of-2-check.patch
mm-damon-lru_sort-remove-duplicated-min_region_sz-power_of_2-check.patch
mm-damon-document-region-size-validation-in-damon_set_regions.patch
mm-damon-core-remove-start-end-check-in-damon_set_region_system_rams.patch
mm-damon-sysfs-remove-region-size-validation.patch
mm-damon-core-stop-ctxs-in-damon_start-before-returning-an-error.patch
samples-damon-mtier-do-not-stop-first-context-for-damon_start-failure.patch
mm-damon-core-make-damon_stop-never-fails.patch
mm-damon-sysfs-ignore-damon_stop-return-value.patch
mm-damon-reclaaim-ignore-damon_stop-return-value.patch
mm-damon-lru_sort-ignore-damon_stop-return-value.patch
mm-damon-core-change-damon_stop-return-type-to-void.patch
samples-damon-mtier-stop-all-contexts-with-single-damon_stop-call.patch
mm-damon-core-wait-ctx-stop-in-damon_call-before-reruning-an-error.patch
samples-damon-wsse-do-not-stop-ctx-for-damon_call-failure.patch
samples-damon-prcl-do-not-stop-damon-for-damon_call-failure.patch