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 0D05743CED8 for ; Mon, 13 Jul 2026 14:58:00 +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=1783954683; cv=none; b=JIVkNM0tjNjVrxgDn3YX8A3yjTLtsXqez6epgvw1zdyQtwl6qNQD2ESv5JSbj2VxVhTjSA5bSI69Dl8NHhz6r2479NhDDz2sTFIMuEVw0tM7rcxj+/71gUhIse846UtsgoL9/tv2ceFzOwSCgleW9HvtrD8Uhs9hBTg/Mcp3OA8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783954683; c=relaxed/simple; bh=+N+ovGCZ/CpD7PcvlBGmZhzz0VVOwtWFR4iOlX4ozZE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aGtvoYgN/YL9QFapQEyqN34dv8sj2Zk+lZo1qSEyWSsaMSYWB8pps/kYpBpwwAvY2mwChpPuc76FcIHUcOGNM6tccOEYq1f1pyBUlYwbTsJSxZ64ADytB98mk+1mbk6HdDQBMkwT1/EfgvadOnJ07n7FWKMRf3WVYofX6PgUvik= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jLnWhb2h; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jLnWhb2h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA9631F00A3A; Mon, 13 Jul 2026 14:57:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783954680; bh=O9IHhEysy4K1XDV8ILNBXnZfEoRXPcuGiIJwTEJG9A8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jLnWhb2hvjgVavg7uG3FOj//cEvdlPm9+N62yZemwjayc9yLYWpEQwlw7tNYj/LCW C0VPmrhjDT5Y8xHPCFKq60aQw4Dk+mYEejoj/21kqhqWcMv/VJjWQOsSFPzLlfYLbU kah9J5CLOAgXqbx4iSZksfZKFsxi0MMBWw22q04WleVqmUjghadKJ72ZAGandIFHXF vtyRKU5b8zxtBIBGWztGxd7NtACMf7qBsoIXA9ahsEPM8oMljuoSzOSnAvIC5rBdPw 5ftJLutSlS8JtS4NgWI+VpSi+M/qDsSm7WjiVh6Qv7pUWk/AtorsxNbvdLXfpxjNGI mSkALU5/cchvw== From: SJ Park To: Harish CS Cc: SJ Park , damon@lists.linux.dev Subject: Re: Regarding additional fixes for on node memcg quota metric issues Date: Mon, 13 Jul 2026 07:57:51 -0700 Message-ID: <20260713145752.40192-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hello Harish, On Mon, 13 Jul 2026 12:32:17 +0530 Harish CS wrote: > Hello SJ, > > I came across the Sashiko review of damos_get_node_memcg_used_bp(), which > identified possible unsigned underflow, division-by-zero, and 32-bit > overflow issues in thenode_memcg_{used,free}_bp quota metric calculation. > I saw your response that you planned to work on these findings separately. > I am a newcomer to DAMON and upstream kernel development, and I am > interested in contributing to this work. Are these issues still open,and > would it be okay for me to work on them? Yes, please feel free to work on it and send patches! :) > > And I would appreciate some initial direction on the approach on validating > the fix. I don't think it is easy to be tested. Many Sashiko-found bugs are theoretically possible but not very common. Maybe you could run DAMON selftests, kunit tests and/or even DAMON test suite for correctness [1] and ensure your change doesn't regress at least existing tests? > > Please let me know whether this would be a reasonable starting point or if > you would recommend a different approach. I think this is a reasonable starting point. Thank you for considering contribution! > > Parent Bug Discussion: > https://lore.kernel.org/20260329153425.47097-1-sj@kernel.org/ > Thank you for your time and guidance. > > Regards, > Harish C S > [1] https://github.com/damonitor/damon-tests/tree/master/corr Thanks, SJ