From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2D00312B94; Sat, 18 Apr 2026 07:55:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776498904; cv=none; b=ApdE1U2S6PehOcdNKVcXIQ3tu3lYkC9+GZLrS01ffwk7h0AOQA2I4FzUdAE3oqOWXeS4EDVhU5bG7ZD2Yz5EouRbLvQXtjxRygnnQDbWFYgeimLTefJYaiT5taCATzNTWHVcEtuCNDgpO3KNU8N/IPt8QzgAke3BlexhwMuQGgc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776498904; c=relaxed/simple; bh=lURGarISh0ggdKyi1RXHzR4triaLmhvlvzD+gY3gDEs=; h=Date:To:From:Subject:Message-Id; b=JIPnTqP+aZya+Vta2EmidUyonnVseYQOub+SIkAxx1qKdHznKBXMewJOb2eu9aBzn/v+XMJ+KYT3UkyalNoMeXaOHRrk8Iw68lWqJwxCgooRlkJLeGrK3vkA3hRL0rYqXNIJXehTKiErvUhRFS78QB6ORvV4Vs8Y4VKxU/8l3V0= 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=eyJjJ0Rz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="eyJjJ0Rz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5EC26C19424; Sat, 18 Apr 2026 07:55:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1776498903; bh=lURGarISh0ggdKyi1RXHzR4triaLmhvlvzD+gY3gDEs=; h=Date:To:From:Subject:From; b=eyJjJ0RzCh09VY4TjVs32+QOWzI2ojAkISvAmT8eLqp8sHBpfsXQnhEygNKVQ0cQE r15zug/xQSlNqvYflFjBE7zIQrCQf4llrxSndkGaW5CczJMVv/pLlTFEp4n08hmk1D qZPrdZxNv0PP4EYXkav7s5gcNTvKpL6FSkIcBZH8= Date: Sat, 18 Apr 2026 00:54:57 -0700 To: mm-commits@vger.kernel.org,stable@vger.kernel.org,sj@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] docs-admin-guide-mm-damon-reclaim-warn-commit_inputs-vs-param-updates-race.patch removed from -mm tree Message-Id: <20260418075502.5EC26C19424@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: Docs/admin-guide/mm/damon/reclaim: warn commit_inputs vs param updates race has been removed from the -mm tree. Its filename was docs-admin-guide-mm-damon-reclaim-warn-commit_inputs-vs-param-updates-race.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: SeongJae Park Subject: Docs/admin-guide/mm/damon/reclaim: warn commit_inputs vs param updates race Date: Sun, 29 Mar 2026 08:30:49 -0700 Patch series "Docs/admin-guide/mm/damon: warn commit_inputs vs other params race". Writing 'Y' to the commit_inputs parameter of DAMON_RECLAIM and DAMON_LRU_SORT, and writing other parameters before the commit_inputs request is completely processed can cause race conditions. While the consequence can be bad, the documentation is not clearly describing that. Add clear warnings. The issue was discovered [1,2] by sashiko. This patch (of 2): DAMON_RECLAIM handles commit_inputs request inside kdamond thread, reading the module parameters. If the user updates the module parameters while the kdamond thread is reading those, races can happen. To avoid this, the commit_inputs parameter shows whether it is still in the progress, assuming users wouldn't update parameters in the middle of the work. Some users might ignore that. Add a warning about the behavior. The issue was discovered in [1] by sashiko. Link: https://lore.kernel.org/20260329153052.46657-2-sj@kernel.org Link: https://lore.kernel.org/20260319161620.189392-3-objecting@objecting.org [1] Link: https://lore.kernel.org/20260319161620.189392-2-objecting@objecting.org [3] Fixes: 81a84182c343 ("Docs/admin-guide/mm/damon/reclaim: document 'commit_inputs' parameter") Signed-off-by: SeongJae Park Cc: # 5.19.x Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/damon/reclaim.rst | 4 ++++ 1 file changed, 4 insertions(+) --- a/Documentation/admin-guide/mm/damon/reclaim.rst~docs-admin-guide-mm-damon-reclaim-warn-commit_inputs-vs-param-updates-race +++ a/Documentation/admin-guide/mm/damon/reclaim.rst @@ -71,6 +71,10 @@ of parametrs except ``enabled`` again. parameter is set as ``N``. If invalid parameters are found while the re-reading, DAMON_RECLAIM will be disabled. +Once ``Y`` is written to this parameter, the user must not write to any +parameters until reading ``commit_inputs`` again returns ``N``. If users +violate this rule, the kernel may exhibit undefined behavior. + min_age ------- _ Patches currently in -mm which might be from sj@kernel.org are mm-damon-core-disallow-time-quota-setting-zero-esz.patch mm-damon-core-disallow-non-power-of-two-min_region_sz-on-damon_start.patch