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 058AD1D95A3; Wed, 29 Jul 2026 04:15:12 +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=1785298517; cv=none; b=SD+h46HzXsIuYERPOT+ZoMC778303Pq7oGXgVraPY22oDP1lN26e392qPdJI6uBzjMnMFOLKt3boIoP05+JV4vmSwykuF0uZrEXEGPmY7vTqZaduhwUdqBDxEDfr4WjJcGwRvMpw8XrjeJ7AhE1hedlZ9OM/U1bA5vcH3AiVX00= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785298517; c=relaxed/simple; bh=rKM/FL2z/NZhzb5btd1oBo0htLlgl6obJ+Jp+RdSJt8=; h=Date:To:From:Subject:Message-Id; b=A/3KzjWPwHHx8r1sIDuuNYVHkj0OpY/Po/0Cq+400Hn/SfQR2mJen8jM4u8bqhECczAivNqH+ctzc483icOILQ4vr1m55AvSaPEmt78LtH7q9R0ZumaJPpIpZSIBF7Fou6P9j1+XPJhEEqkvJbmiefiuOdsGhCJiVrCOBkPfiKA= 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=qYkzASFt; 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="qYkzASFt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2C241F00A3A; Wed, 29 Jul 2026 04:15:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1785298511; bh=LTposx6UsXzxiHFk8Ms+kfSUz9hqqYWuscA1hA1K4TY=; h=Date:To:From:Subject; b=qYkzASFt7wCHn5IIk1UW/NDGhxwzUoFkas0VreMPqoXkkW/NrG9Ynj0e7e3My8X/U 9VQuoRFtZtIMViSPO0hIXuEsaOllwt7WXHlRbrFpwZ5Vl0ZJifW80CrAvFMqSUP5Bx rIfep02It7n+N1EYMZD9NAFQM0wqFymZrZq8CAQM= Date: Tue, 28 Jul 2026 21:15:11 -0700 To: mm-commits@vger.kernel.org,zenghui.yu@linux.dev,stable@vger.kernel.org,sj@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] samples-damon-mtier-handle-damon_start-failure.patch removed from -mm tree Message-Id: <20260729041511.C2C241F00A3A@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: samples/damon/mtier: handle damon_start() failure has been removed from the -mm tree. Its filename was samples-damon-mtier-handle-damon_start-failure.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: samples/damon/mtier: handle damon_start() failure Date: Sun, 28 Jun 2026 14:54:42 -0700 damon_sample_mtier_start() callers assume it will clean up resources when it fails. And the function does the cleanup for context buildup failures. However, it is not doing the cleanup for damon_start() failure. As a result, when damon_start() fails, it could leak the memory for DAMON context. Also, if damon_start() fails for only the second context, the first context will indefinitely run, and avoid starting other DAMON contexts since it is running in the exclusive mode. Stop possibly started DAMON context and free the contexts in case of the failure to fix the issues. Note that the issue can reliably be reproduced because the module calls damon_start() in the exclusive mode. For example, $ sudo damo start $ echo Y | sudo tee /sys/module/damon_sample_mtier/parameters/enabled $ sudo cat /proc/allocinfo | grep damon_new_ctx Because the first command is running another DAMON instance, the second command fails the damon_start() call because the new DAMON instance cannot exclusively run. And without this fix, by repeating the second and the third commands above, we can show the memory consumption is only increasing due to the leaks. It requires the sudo permission though. The issue was discovered [1] by Sashiko. Link: https://lore.kernel.org/20260628215447.96166-4-sj@kernel.org Link: https://lore.kernel.org/20260608112455.274231F00893@smtp.kernel.org [1] Fixes: 82a08bde3cf7 ("samples/damon: implement a DAMON module for memory tiering") Signed-off-by: SJ Park Reviewed-by: Zenghui Yu Cc: # 6.16.x Signed-off-by: Andrew Morton --- samples/damon/mtier.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/samples/damon/mtier.c~samples-damon-mtier-handle-damon_start-failure +++ a/samples/damon/mtier.c @@ -177,6 +177,7 @@ free_out: static int damon_sample_mtier_start(void) { struct damon_ctx *ctx; + int err; ctx = damon_sample_mtier_build_ctx(true); if (!ctx) @@ -188,7 +189,15 @@ static int damon_sample_mtier_start(void return -ENOMEM; } ctxs[1] = ctx; - return damon_start(ctxs, 2, true); + err = damon_start(ctxs, 2, true); + if (!err) + return 0; + + if (damon_is_running(ctxs[0])) + damon_stop(ctxs, 1); + damon_destroy_ctx(ctxs[0]); + damon_destroy_ctx(ctxs[1]); + return err; } static void damon_sample_mtier_stop(void) _ Patches currently in -mm which might be from sj@kernel.org are mm-damon-adjust-isolated-pages-stat-for-damos_migrate_hotcold.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 mm-damon-core-remove-comment-and-test-for-nr_to_bp-divide-by-zero.patch mm-damon-core-s-damon_max_nr_accesses-damon_nr_samples_per_aggr.patch mm-damon-core-s-accesses_bp_to_nr_accesses-sample_bp_to_count.patch mm-damon-core-s-nr_accesses_to_accesses_bp-sample_count_to_bp.patch mm-damon-core-s-nr_accesses_for_new_attrs-nr_samples_for_new_attrs.patch mm-damon-core-update-probe-hits-for-new-parameter-commit.patch mm-damon-core-handle-unreset-probe_hits-in-probe_hits_mvsum.patch mm-damon-core-introduce-damon_probe-weight.patch mm-damon-core-ask-apply_probes-ops-callback-to-set-sampling-address.patch mm-damon-paddr-set-samples-in-apply_probes-if-requested.patch mm-damon-core-ask-apply_probe-to-return-max-probe-hits-weighted-sum.patch mm-damon-core-implement-damon_probe_hits_wsum.patch mm-damon-paddr-respect-return_max_wsum.patch mm-damon-core-use-abs_diff-instead-of-abs.patch mm-damon-core-extend-merge-function-to-work-with-probe-hits.patch mm-damon-core-disallow-probe_hits-overflow-on-attrs-only-monitoring.patch mm-damon-core-validate-params-for-probe-hits-weighted-sum-overflow.patch mm-damon-core-disable-access-monitoring-when-probe-weights-are-set.patch mm-damon-core-set-samples-in-apply_probes-if-probe-weights-are-set.patch mm-damon-core-s-max_nr_accesses-max_merge_score-in-kdamond_fn.patch mm-damon-core-get-merge-threshold-from-probe-hits-when-weights-are-set.patch mm-damon-core-implement-damon_has_probe_weight.patch mm-damon-sysfs-implement-probe-weight-file.patch docs-mm-damon-design-document-attrs-only-monitoring.patch docs-admin-guide-mm-damon-usage-document-weight-sysfs-file.patch docs-abi-damon-document-probe-weight-file.patch mm-damon-core-skip-aging-from-repeated-aggressive-merging.patch mm-damon-core-hide-private-damon_region-fields.patch mm-damon-core-hide-private-damon_target-fields.patch mm-damon-core-hide-private-damos_quota_goal-fields.patch mm-damon-core-hide-private-damos_quota-fields.patch mm-damon-core-hide-private-damos_filter-fields.patch mm-damon-core-hide-private-damos-fields.patch mm-damon-core-hide-private-damon_filter-fields.patch mm-damon-core-hide-private-damon_probe-fields.patch mm-damon-sysfs-do-not-directly-access-damon_ctx-ops.patch mm-damon-core-hide-core-private-damon_ctx-fields.patch mm-damon-core-avoid-infinite-kdamond_merge_regions-internal-loop.patch mm-damon-tests-core-kunit-catch-test-failure-in-test_merge_regions_of.patch mm-damon-vaddr-drop-last-same-folio-access-check-optimization.patch mm-damon-paddr-drop-last-same-folio-access-check-reuse-optimization.patch mm-damon-sysfs-read-addr_unit-only-once-in-damon_sysfs_apply_inputs.patch mm-damon-sysfs-read-ops_id-only-once-in-damon_sysfs_apply_inputs.patch mm-damon-core-initialize-damos-last_applied.patch mm-damon-core-kunit-check-region-count-before-testing-in-split_at.patch mm-damon-vaddr-kunit-check-region-count-in-three_regions-test.patch mm-damon-core-kunit-handle-region-split-failure-in-filter_out.patch mm-damon-core-kunit-skip-wrong-dest-walk-in-commit_dests_for.patch mm-damon-core-kunit-skip-wrong-quota-goal-walk-in-commit_quota_goals.patch mm-damon-core-kunit-skip-wrong-region-walk-in-commit_target_regions.patch mm-damon-ops-common-use-nr_accesses-moving-sum-for-quota-score.patch mm-damon-core-handle-region-split-failure-in-apply_min_nr_regions.patch