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imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=BE59L+tX; spf=pass (imf06.hostedemail.com: domain of sj@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=sj@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1792946901; b=DGhFi78I4MkgbRnB3yUe0kY0xEYDDW1u1iU+yLmiNv4Q8dWNTR80vyz8cpxLlYbNsZuwrT WdodBdXdpGk49v0dVBoUoy4NvLe030JIF7bwVURBDRGjgjwg9ORIltp2frH04O2zhGjY3P aBz0l+mFk3M7zuFbufw/dd33A9xTu30= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 3BB7E600AA; Sun, 25 Oct 2026 16:48:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95F6E1F01825; Sun, 25 Oct 2026 16:48:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792946899; bh=Q80p5MCUlafYdcYjwuOtEqPOJb6ACREJHt1LW8otA0U=; h=From:To:Cc:Subject:Date; b=BE59L+tXgKsr6xmG/v2ova9IBI5Ez0pYWp5yRRfHpJgTtL9+iX+yTdY7eS/Xfk/w3 jLfAWkaugebck40qc3kL1tzD462m8fb9d9PbCdA/lv8PyLcTzF89tARN3sj0FKPrwM nYiwCeVa5orPCVQfJE0AWBT8xENUJk7d0b0LZDlN6868enbv5i7EQvD2PCzSyEEEjf tO23WIIWmat/Dfb7et2QEjrCRjPBBxdOjMDHEzsgnkd7iaRdkq9KWinnBkGXn0X8+c gaD4QRhwd95iFVVHPgRE4ud8rrqPSCMadF1j0/kIQLo3UHmS43f1Hf44zdJZ1hYX0u wZI+FrfvFOGHg== From: SJ Park To: Andrew Morton Cc: SJ Park , stable@vger.kernel.org, Fernand Sieber , Jiayuan Chen , SeongJae Park , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 0/3] mm/damon: fix three race bugs in sysfs and core Date: Sun, 25 Oct 2026 09:48:03 -0700 Message-ID: <20261025164808.152048-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 231E7180002 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-Stat-Signature: urf4tgidg5occt83a3ni46wh5d737qyi X-HE-Tag: 1792946900-101508 X-HE-Meta: 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 aE8aj9F+ Wh2uLT2+hdcWhXCbYJcSAjz0eXOCC+B6msY6TwYdZOZz4igi4+R+upIBtza9c71XnUWgTFIIEMj27n3wqLl6gfkgmVvetSNWIoybyKQTPEWQ1Jt+OtPFI6UzK0YFOekEGsYD0ZPt85je1pJltBetzPECs8ISQpmTI0Owtz5aF/SX+N5r8h70Ww9Z68CHtnI10LiF6c/3W66lIWOLSRkkK2c7x/FIlDuvao5rtdK6ROBzHu7Q= 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. Changes from RFC - RFC: https://lore.kernel.org/20261024193351.87130-1-sj@kernel.org - Rebase to latest mm-new. - Drop RFC tag. 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: 34b81edd2a3300a88493222637ea010223c00ecd -- 2.47.3