[merged mm-stable] mm-damon-core-set-ctx-call_controls_obsolete-in-damon_new_ctx.patch removed from -mm tree

[merged mm-stable] mm-damon-core-set-ctx-call_controls_obsolete-in-damon_new_ctx.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/damon/core: set ctx->call_controls_obsolete in damon_new_ctx()
has been removed from the -mm tree.  Its filename was
     mm-damon-core-set-ctx-call_controls_obsolete-in-damon_new_ctx.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: SJ Park <sj@kernel.org>
Subject: mm/damon/core: set ctx->call_controls_obsolete in damon_new_ctx()
Date: Wed, 2 Sep 2026 18:03:31 -0700

damon_ctx->call_controls_obsolete is used to disallow damon_call()
requests when the request cannot be served.  The field is unset and set
when the context execution is started and terminated, respectively.  The
intention is to allow damon_call() requests only while the context is
actively being executed.

damon_ctx constructor, damon_new_ctx() unsets the field, though.  As a
result, passing the damon_ctx parameter that never successfully
damon_start()-ed to damon_call() can indefinitely hang.  The callers
should ensure to avoid the case.  Such parameter validation is not always
simple.  Actually such bugs in DAMON_RECLAIM and DAMON_LRU_SORT have been
found and fixed [1].

Set the field in damon_new_ctx(), so that DAMON API callers can pass the
context parameter to damon_call() without the additional check.

Link: https://lore.kernel.org/20260903010334.93622-3-sj@kernel.org
Link: https://lore.kernel.org/20260803134646.16640-1-sj@kernel.org [1]
Signed-off-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/damon/core.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- a/mm/damon/core.c~mm-damon-core-set-ctx-call_controls_obsolete-in-damon_new_ctx
+++ a/mm/damon/core.c
@@ -933,6 +933,7 @@ struct damon_ctx *damon_new_ctx(void)
 	INIT_LIST_HEAD(&ctx->adaptive_targets);
 	INIT_LIST_HEAD(&ctx->schemes);
 
+	ctx->call_controls_obsolete = true;
 	prandom_seed_state(&ctx->rnd_state, get_random_u64());
 
 	return ctx;
@@ -2206,10 +2207,6 @@ int damon_kdamond_pid(struct damon_ctx *
  * synchronization.  The return value of the function will be saved in
  * &damon_call_control->return_code.
  *
- * Note that this function should be called only after damon_start() with the
- * @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.
_

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

mm-damon-sysfs-schemes-read-sysfs_filter-addr_range-only-once.patch
mm-damon-sysfs-schemes-read-sysfs_filter-sz_range-only-once.patch
mm-damon-core-return-an-error-from-damos_commit_filter_arg.patch
mm-damon-core-disallow-max-min-damos-filter-range-arguments-commit.patch
mm-damon-sysfs-schemes-drop-centralized-filter-range-arg-validations.patch
mm-damon-sysfs-schemes-use-switch-case-in-add_scheme_filters.patch
mm-damon-core-kunit-extend-damos_commit_filter_for-for-wrong-input.patch
mm-damon-core-kunit-test-invalid-damos-filter-commits.patch
mm-damon-api-introduce-damon_filter_type_hugepage_size.patch
mm-damon-core-commit-hugepage_size-type-damon-filter.patch
mm-damon-ops-common-support-hugepage_size-damon-filter-matching.patch
mm-damon-sysfs-add-minmax-files-under-probe-filter-directory.patch
mm-damon-sysfs-support-hugepage_size-probe-filter.patch
docs-mm-damon-design-update-for-hugepage_size-probe-filter.patch
docs-admin-guide-mm-damon-usage-update-for-hugepage_size.patch
docs-abi-damon-update-for-hugepage_size-probe-filter.patch
mm-damon-api-remove-nr_damos_filter_types.patch
mm-damon-core-use-abs_diff-in-damon_feed_loop_next_input.patch
mm-damon-core-use-mult_frac-in-damon_feed_loop_next_input.patch
mm-damon-core-set-damon_ctx-walk_control_obsolete-in-damon_new_ctx.patch
mm-damon-core-document-damon_call-damon_start-race-hang-issue.patch
mm-damon-paddr-remove-pa-parameter-from-damon_pa_filter_pass.patch
mm-damon-tests-core-kunit-test-eligible_mem_bp-commitment.patch
mm-damon-tests-core-kunit-add-probe_hits_wsum-damos-filter-commit-test.patch
selftests-damon-sysfs_memcg_path_leak-fail-only-for-real-damon-leak.patch
docs-mm-damon-design-clarify-bp-is-basis-point.patch
mm-damon-core-introduce-damos_quota_goal-complement.patch
mm-damon-core-add-complement-argument-to-damos_new_quota_goal.patch
mm-damon-sysfs-schemes-support-quota-goal-complement-flag.patch
mm-damon-tests-core-kunit-test-quota_goal-complement-commit.patch
selftests-damon-sysfssh-test-quota-goal-complement-flag-file.patch
docs-mm-damon-design-document-damos-quota-goal-complement-flag.patch
docs-admin-guide-mm-damon-usage-update-for-quota-goal-complement-file.patch
docs-abi-damon-update-for-quota-goal-metric-complement-sysfs-file.patch