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 55F114F93A6 for ; Mon, 19 Oct 2026 13:42:04 +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=1792417325; cv=none; b=dcd9FUMppkWEv9or+pMukfF6GahZFHV7QBqY1mpHrTtPm3X6z1ZqfZFNVN3kEKecyLVUfyqNCHj1gxbF/0Jv9G19H5SrjMmVkNeJXC3ipL26baev93kc9CmUcFZ3uPBUTsPYS/07ZwfN6AHqrdNa3mKgj37ANpIzCKsmisdKPpQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792417325; c=relaxed/simple; bh=DM3EsX13nPtfScUM6UQ/SC5JIx0WYvza0w3BjZivu8E=; h=Message-ID:From:Subject:To:Cc:In-Reply-To:References:Content-Type: Date; b=H9QCs3Mz2n5qSrtPKs0zzFpCORshw5e7I9ioMQF1JP3UsRs90GppG0BteRAFOzmpJvOk29IsCtUcUZDOnyBSowmbwytw/qAXAECz3Px9OUzGS5Gi7YUjVez9f1XYtzvMvZt3qoWoMWVKB4eUyHONJrAiUAreNyZpEbaJiEypb40= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WDHfKalp; 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="WDHfKalp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CA5B21F000C4; Mon, 19 Oct 2026 13:42:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792417324; bh=/VDQm9uqPREk5uSHazeBU9qa81dt/blg2PAeeA3FgrM=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=WDHfKalp/9iwJZZ6E2Er9iQBK5FpyKXjTPiZJzTxvdXLIJAonbTGSaMsNzm8RSNkI /k9bc0XbnSXtZxFHN44Hmz/Cbrr3IPw4+1gENicuV0MBpRHdcwCDWWdOcjL6r1OjAn qDIcasK+Wk1uskmY/bdgPRto1EmNzTQMeVoHo+78/o0z8tcGHucCR07CA3jslNJqi9 3u4XkGxS4osq+CDHzB/vdl9bURWWtQGmR4cFuQXWoyV3U9iw8zgKu1s/WRA0F6AaJ/ HXi3+vUSegYJMKz3l5bk6uYE/mvEiuIffmtHnyJWjFR3P4vwgUfj/d/Yx/TjH3JYbd niLr++kKV20tw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH v2] mm/damon/core: filter out damos address filter-split failed region Reply-To: sashiko-reviews@lists.linux.dev To: "SJ Park" Cc: damon@lists.linux.dev In-Reply-To: <20261019133856.86835-1-sj@kernel.org> References: <20261019133856.86835-1-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 19 Oct 2026 13:42:02 +0000 Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: > When an address type DAMOS filter is configured, DAMOS tries to split > the region for the filter range, and apply DAMOS action to the filter-in > region. The split operation (damon_split_region_at()) could fail from > allocation failure under extreme memory pressure. In the case, DAMOS > action could be applied more or less than expected, ignoring the address > filter. >=20 > The issue only rarely happens under extreme memory pressure. No crash > or leak happens. Occasionally not applying the action to a few regions > shouldn't be a real problem. But applying the action to a region that > the user has excluded via address filter could be a surprise depending > on the use case. It is only theoretical. No such real case is found > yet. >=20 > Filter out the entire region if the split is failed. Update > damos_filter_match() signature to receive the error from split. Also > update kunit tests for the updated signature. >=20 > The issue was discovered [1] by sashiko. >=20 > [1] https://lore.kernel.org/20260801203121.117449-1-sj@kernel.org >=20 > Fixes: ab9bda001b68 ("mm/damon/core: introduce address range type damos f= ilter") > Cc: # 6.6.x > Signed-off-by: SJ Park Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261019133856.8683= 5-1-sj@kernel.org?part=3D1