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 D02CE25FA29; Wed, 7 Oct 2026 00:52:12 +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=1791334334; cv=none; b=HOY00ig9xKQONOXH/3dSj+97uWKmJwRKzJCCLMnnI3rygZZ5uFHV2T4yTTmj9YXSzqGFKYRxXLQqjGJsJLVYNCE6ioSh4agaekt+JO/CCxIwkOYhk/y9LlE/aECatZpKYYQybMnB+R47Zj1QIAE/SzLhKaFy1va9A5YBMyoQeIU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791334334; c=relaxed/simple; bh=nLD1dZEadX20gqMzad4BfHsg7LbDYcpgK3/souXYe/I=; h=Date:To:From:Subject:Message-Id; b=gKGDksvTmVN44AtG9s3s92IrvyS9ZSze3CIItZXktJrgnlbsa4H/xu4ugicrav/GVowVsG6e770XXQTbOopNU4dpYP7MWoyX0Z2iu7Tovfmsbkv77CYraAsvpfAEuxoNm1cRPfLKTDO0965QrYmP9ku4THtKlqebZrCTIDwSBvk= 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=lTQ4xq1A; 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="lTQ4xq1A" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6F9D1F0089D; Wed, 7 Oct 2026 00:52:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1791334332; bh=CKGIU5jQNUwTCxP1AcbvybQFJvYWQSfmxMDevOBYvvE=; h=Date:To:From:Subject; b=lTQ4xq1ATbfEI0CG/h4f4NYnFAeV8GRl6THwIgW1sqNfVO2AgXO7XHWIK5T0acmNH DXwKhzDOI01F6lYie/PB7FRpFkFoUyT9ZlFX9myPunhqLauc9YJeGwwYivP0JHtFcK SpONrzgRTUsySgTLZa5+hmKHwxG+p5Fc3Q+bzbVs= Date: Tue, 06 Oct 2026 17:52:12 -0700 To: mm-commits@vger.kernel.org,usamaarif642@gmail.com,stable@vger.kernel.org,sj@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-damon-core-handle-extreme-memory-state-in-damon_get_node_mem_bp.patch removed from -mm tree Message-Id: <20261007005212.A6F9D1F0089D@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: handle extreme memory state in damon_get_node_mem_bp() has been removed from the -mm tree. Its filename was mm-damon-core-handle-extreme-memory-state-in-damon_get_node_mem_bp.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: handle extreme memory state in damon_get_node_mem_bp() Date: Tue, 1 Sep 2026 06:18:47 -0700 In an extreme and unlikely situation, si_meminfo_node() might let the caller show zero total ram. That could cause a divide by zero in damon_get_node_mem_bp(). It could also show free memory larger than the total memory. This could cause underflow and make DAMOS temporarily make unexpected behavior. Thanks to safety guards in the auto-tuning feedback loop, that should not be a real problem, though. Fix the problems by respectively returning 100% and 0% for used and free memory queries in the corner cases. The issue was discovered [1] by Sashiko. Link: https://lore.kernel.org/20260901131850.98037-7-sj@kernel.org Link: https://lore.kernel.org/20260328133216.9697-1-sj@kernel.org [1] Fixes: 0e1c773b501f ("mm/damon/core: introduce damos quota goal metrics for memory node utilization") Signed-off-by: SJ Park Signed-off-by: Andrew Morton Cc: Usama Arif Cc: # 6.16.x --- mm/damon/core.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/mm/damon/core.c~mm-damon-core-handle-extreme-memory-state-in-damon_get_node_mem_bp +++ a/mm/damon/core.c @@ -2810,6 +2810,13 @@ static __kernel_ulong_t damos_get_node_m } si_meminfo_node(&i, goal->nid); + if (!i.totalram || i.totalram < i.freeram) { + if (goal->metric == DAMOS_QUOTA_NODE_MEM_USED_BP) + return 10000; + else /* DAMOS_QUOTA_NODE_MEM_FREE_BP */ + return 0; + } + if (goal->metric == DAMOS_QUOTA_NODE_MEM_USED_BP) numerator = i.totalram - i.freeram; else /* DAMOS_QUOTA_NODE_MEM_FREE_BP */ _ Patches currently in -mm which might be from sj@kernel.org are mm-damon-core-use-damon_nr_samples_per_aggr-for-max-merge-threshold.patch mm-damon-core-remove-debug-messages.patch mm-damon-core-remove-debug-messages-fix.patch mm-damon-vaddr-remove-a-debug-message.patch mm-damon-core-validate-number-of-probes-in-valid_probe_params.patch mm-damon-sysfs-remove-probes-number-validation.patch mm-damon-tests-core-kunit-extend-set_regions-test-for-error-case.patch mm-damon-tests-core-kunit-test-=0-size-damon_set_regions-inputs.patch mm-damon-tests-core-kunit-test-overlapping-ranges-for-set_regions.patch mm-damon-tests-core-kunit-test-damon_nr_samples_per_aggr.patch selftests-damon-sysfssh-test-hugepage_mem_bp-quota-goal.patch docs-mm-damon-maintainer-profile-update-ai-review-for-sashiko-replies.patch docs-abi-damon-recommend-subsystem-doc-instead-of-admin-guide.patch mm-damon-core-error-damos_commit_quota_goal-for-zero-target_value.patch revert-mm-damon-lru_sort-error-out-for-10000-active_mem_bp.patch revert-samples-damon-mtier-error-out-for-zero-quota-goal-target-values.patch mm-damon-core-handle-null-ctx-parameter-in-damon_call.patch mm-damon-core-set-ctx-call_controls_obsolete-in-damon_new_ctx.patch mm-damon-reclaim-remove-unnecessary-damon_call-param-validation.patch mm-damon-lru_sort-remove-unnecessary-damon_call-param-validation.patch mm-damon-vaddr-support-prep_probes.patch mm-damon-paddr-move-probe-filter-handling-to-ops-common.patch mm-damon-vaddr-support-apply_probe.patch mm-damon-vaddr-extend-apply_probes-for-hugetlb.patch mm-damon-vaddr-support-pgidle_unset-probe-filter-type.patch mm-damon-api-introduce-damon_filter_type_pgidle_set.patch mm-damon-paddr-support-damon_filter_type_pgidle_set.patch mm-damon-vaddr-support-damon_filter_type_pgidle_set.patch mm-damon-sysfs-support-damon_filter_type_pgidle_set.patch docs-mm-damon-design-update-for-pgidle_set-probe-filter.patch mm-damon-api-introduce-damos_filter_type_probe_hits_wsum.patch mm-damon-api-introduce-damos_filter_type_probe_hits_wsum-fix.patch mm-damon-core-extend-probe_hits_wsum-for-moving-sum-based-calculation.patch mm-damon-core-support-probe_hits_wsum-damos-core-filter.patch mm-damon-sysfs-schemes-rename-sysfs_filter-sz_range-to-range_minmax.patch mm-damon-sysfs-schemes-support-probe_hits_wsum-damos-core-filter.patch docs-mm-damon-design-update-for-probe_hits_wsum-damos-core-filter.patch docs-admin-guide-mm-damon-usage-update-for-probe_hits_wsum-damos-filter.patch 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