From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CDB1D3F8EB3 for ; Fri, 9 Oct 2026 05:56:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791525389; cv=none; b=Y2FPsSnmB3EJ6ThFgxr43yCqu/BANKzoDATc+cHErrzF4KBotng/g7W7acxY0pICDu58btvGnvPWV480Di9hWwgtCvjKlmGgUIF+IPJfi/W2+W+D6DtiKhSTlqVaISXu9IUmrOGsbgqV0lOakSAWoPGevYlrsVTx4xtvp1x5wOM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791525389; c=relaxed/simple; bh=7nCjhpMOwpsSgJUCh8yCbTXU7dWL4tTpLMrPSqdTmak=; h=Date:To:From:Subject:Message-Id; b=SovfBJHlmBXPYmYKhAoBbdGfz+B1zoKWB0pzIbagiOBKK5YK7d+1LDXgPbn4lFeyg6RAK5XnTrhvz/JK3jWyY82puhAboCrJkCxSJhC73ZK0ekpEsgnFaV9SrUyI98852bTAiA4EWwn0EeG4q+pwyWPvDNiPOjCot8GlZGX8/vo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=rlWZU3WJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="rlWZU3WJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4CFB1F000FF; Fri, 9 Oct 2026 05:56:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1791525387; bh=7fZu6IrBA2RRWZ6CXJV8sTNY5GFMpLzoRSqQcck2E60=; h=Date:To:From:Subject; b=rlWZU3WJlcE1qYg7w+m3xNSp7OlT3zaW49dtfw0IzgYrddXlWQI8vqKyvS782M7GC nQnQnMfwKW8DmCfC2Mt/y/TaT+vFczaXDLqtEnWuZNz79WfwG0nAJfUv+fw7zKpkV3 Wab4RzdJtwnblWbxbwqhzkIWCfF0EXfOsupRetwE= Date: Thu, 08 Oct 2026 22:56:27 -0700 To: mm-commits@vger.kernel.org,sj@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-damon-core-error-damos_commit_quota_goal-for-zero-target_value.patch removed from -mm tree Message-Id: <20261009055627.A4CFB1F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/damon/core: error damos_commit_quota_goal() for zero target_value has been removed from the -mm tree. Its filename was mm-damon-core-error-damos_commit_quota_goal-for-zero-target_value.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 Subject: mm/damon/core: error damos_commit_quota_goal() for zero target_value Date: Wed, 2 Sep 2026 18:07:19 -0700 Patch series "mm/damon: move zero damos quota target_value handling to the core layer". Having zero DAMOS quota target value can cause division by zero. DAMON API callers are checking the target value parameters to avoid that. It is easy to make mistakes in some of the multiple API callers. Move that to the core layer. Patch 1 adds the corner case handling into the core layer DAMON parameters validation logic. Patches 2 and 3 remove no more needed DAMON API callers side handling of the corner case in DAMON_LRU_SORT and DMON_SAMPLIE_MTIER, respectively. This patch (of 3): If a DAMOS scheme has a damos_quota_goal of zero target_value, damos_quota_goal() could trigger division-by-zero error. Hence each DAMON API callers should do the zero target_value validation. It is easy to make mistakes. Actually such bugs in DAMON_LRU_SORT and DAMON_SAMPLE_MTIER were found and fixed [1]. It is better to handle the corner case only once in the core layer, instead of multiple places in all DAMON API callers. One straightforward option is using an alternative denominator for the corner case in the damos_quota_goal(). However, the zero target_value is meaningless. In this case, the quota goal is always evaluated as achieved or over-achieved. The quota will only keep being reduced. Simply avoid using zero target_value by adding a check in the core layer DAMOS quota goal parameters validation/commit path, damos_commit_quota_goal(). Update it to return an error in the case. Also update its caller to propagate the error. Link: https://lore.kernel.org/20260903010722.94244-1-sj@kernel.org Link: https://lore.kernel.org/20260903010722.94244-2-sj@kernel.org Link: https://lore.kernel.org/20260803134034.15217-1-sj@kernel.org [1] Signed-off-by: SJ Park Signed-off-by: Andrew Morton --- mm/damon/core.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) --- a/mm/damon/core.c~mm-damon-core-error-damos_commit_quota_goal-for-zero-target_value +++ a/mm/damon/core.c @@ -1211,14 +1211,17 @@ static void damos_commit_quota_goal_unio } } -static void damos_commit_quota_goal( +static int damos_commit_quota_goal( struct damos_quota_goal *dst, struct damos_quota_goal *src) { + if (!src->target_value) + return -EINVAL; dst->metric = src->metric; dst->target_value = src->target_value; if (dst->metric == DAMOS_QUOTA_USER_INPUT) dst->current_value = src->current_value; damos_commit_quota_goal_union(dst, src); + return 0; } /** @@ -1236,14 +1239,17 @@ static void damos_commit_quota_goal( int damos_commit_quota_goals(struct damos_quota *dst, struct damos_quota *src) { struct damos_quota_goal *dst_goal, *next, *src_goal, *new_goal; - int i = 0, j = 0; + int i = 0, j = 0, err; damos_for_each_quota_goal_safe(dst_goal, next, dst) { src_goal = damos_nth_quota_goal(i++, src); - if (src_goal) - damos_commit_quota_goal(dst_goal, src_goal); - else + if (src_goal) { + err = damos_commit_quota_goal(dst_goal, src_goal); + if (err) + return err; + } else { damos_destroy_quota_goal(dst_goal); + } } damos_for_each_quota_goal_safe(src_goal, next, src) { if (j++ < i) @@ -1252,7 +1258,11 @@ int damos_commit_quota_goals(struct damo src_goal->metric, src_goal->target_value); if (!new_goal) return -ENOMEM; - damos_commit_quota_goal(new_goal, src_goal); + err = damos_commit_quota_goal(new_goal, src_goal); + if (err) { + damos_free_quota_goal(new_goal); + return err; + } damos_add_quota_goal(dst, new_goal); } return 0; _ 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