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imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="i/aG3jxE"; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf06.hostedemail.com: domain of sj@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1792870440; b=yB1V6ubddYvlPxBX8mAqMp3YFE46w+EPlU2NHH2WPQf1Lj9TRU6tAyWxdWHjXAICEyKkUV FlZytA11c0c6f79j3BDV4dv653LsOWjHDpfx8yEYL4ezGG1kNMRqpsOyD9y3WVuShH3UZl r+sxopr4BKXKrTlHaAM2WPDkRRnJOiw= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 615F1601DE; Sat, 24 Oct 2026 19:33:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C15F01F01825; Sat, 24 Oct 2026 19:33:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792870439; bh=B+9LPpeyWJrESAgg+ZQjlbIQ+zZneFd2FYznRyvKzQ8=; h=From:To:Cc:Subject:Date; b=i/aG3jxEddkj7xtQ9f3WYVMpUdNeqlPxwj4ciVD5BchuvceGln2DXw8sx1RReEiFR yUVmEz/gLrY0iuGzOCzT4ZOJT0370ye3AB8krrxnKd1wmKG1YW4DrpbEPlesZhv3gf y5buFfvDheBg474TrlT/ICDVbdESfWutV7RXpmfqvU1t/wAp+HSLivn9EOu7N+z0S1 ABLrHwhEMrzZLab5gnwJDJ6x81N/vjKB0x6VwpDFANxz0cRUq32O4u92UzI5ARUJ8a Yp/czdUdLef0U0qPRlP+nfgwhdj3z14nxxu1b8/M4Gugutxah8A+1MBS8RxE0UYQ4e AbWFYk7IdHHKQ== From: SJ Park To: Cc: SJ Park , stable@vger.kernel.org, Andrew Morton , Fernand Sieber , Jiayuan Chen , SeongJae Park , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 0/3] mm/damon: fix three race bugs in sysfs and core Date: Sat, 24 Oct 2026 12:33:46 -0700 Message-ID: <20261024193351.87130-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: F2164180003 X-Stat-Signature: 6u3n3uew7cdr55q3jhiu5ixit7f3surq X-Spam-Status: No, score=-14.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1792870439-59686 X-HE-Meta: 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 pLYOmZzE ivkKv0vU8C0pu56qXRBEG997dJ+BPgnMDV+bA93tj7biEp1N7gH2UxBAcgdFMLXUKaHblwwd2qSVBcyn7k9eRSwutED1LZbCHeNBL3mikDGo9+K0n1WUIkLUGq6MDfonAOE2yXy4jkfx1puXK2UOseak1H1uRPnRfkRxgqfLgSO+jgHT7QRqaX+snwIMt7wMtyg4Ed0l2aALMY9rYdJUay9R6dSv8sWRURMgBtcHsi3pNPjI= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 There are three race condition bugs in DAMON sysfs interface and the core layer. User impacts are not critical but better to fix sooner than later. Patch 1 fixes a toctou bug in DAMON sysfs interface that can mess up DAMOS auto-tuning. Patches 2 and 3 move static variables that can be wrongly shared with multiple kdamonds and therefore make DAMON monitoring results be a little more indeterministic. Note for Andrew. These are not urgent but better to take the hotfix track in my humble opinion. SJ Park (3): mm/damon/sysfs-schemes: hold damon_sysfs_lock in target_metric_store() mm/damon/core: move static variable last_nr_regions to damon_ctx mm/damon/core: move static variable rotation to damon_ctx include/linux/damon.h | 10 ++++++++++ mm/damon/core.c | 10 +++++----- mm/damon/sysfs-schemes.c | 3 +++ 3 files changed, 18 insertions(+), 5 deletions(-) base-commit: f390255d9de653f4e7a9bae8c9a5ad881ad25a87 -- 2.47.3