From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792457033; b=bLyXV8qE1eoCl/6Sr0GgWjxcKQuOkvqWsUBVe6DgvxSh5gj5pffuHYHtYpset61ezc0x aU5WzbKdkNUF7xXH5U0ouEp0Vn1jf9v0fRlT424IEMw33iyejDwqJ9aFKJ4ebZakNuZjm vchs5kgZdaX+jsw0xsrx7hyZ3UH4TXa3kfnaQp1HJjmdRaAqRmzQa4EtUcDB5HnhJ1n7r WzYiBrI9kgsN21kvOtVnnj8WlhWmsM8otT4R9sBsCdKI9dclGOZnNpTar4eQRbU9cjPFc ydVP6CzvYqPRg8yYud8K6G/L99iOHZfOvxXox/Nt/i8iotwO7akidicwSq1INNi+jgA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792457033; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=oGyDIK5rdrER74aX0XxP0tN5lqLfzpieYyIynIXcrfU=; b=dTe8gZZRddO1eorSQAXgCUF6sOPHQW9RzGGHy7G9bajaz7FmS6IRCm6FzngLQUYj4UP1 +x0JvDSCcFXt5wF7V2qxYgr30qQ0rna1kUUSwu2nzloQn/tTchn6PkyZtUQoWQ0E9allo 2yigOpi6dVzJ+zLktSlk2bDw4DD99c6bynxfhMUbPLkbqKieNqWT9C4eXlUzgoAFfUxiy 9Egzw+IkfwICR0UOOoDinfyZR2y26DGpd2UxQ4kuFAPSLvET8fkEpaHYHhxZ4QvGBRAa1 1AWofkcr/ab7bONok6env4oh7TLQ348hzdn8wZ/IDp95ZENOc2pu/loExW7/vrwAJiw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=PtujFuUG; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1EC5C606A31C for ; Tue, 20 Oct 2026 00:43:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=PtujFuUG Received: by smtp.kernel.org (Postfix) with ESMTPSA id A12851F000C4; Tue, 20 Oct 2026 00:43:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792457032; bh=oGyDIK5rdrER74aX0XxP0tN5lqLfzpieYyIynIXcrfU=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=PtujFuUGek48l1bUlVqxFg+OsZvDnl6Xbu63rX0Py96D0tOTkJC0VosJfXp7eoQiW 5GtMUHUwGQRKzbU/H+ZvhGcZlY4BUaCFAzzwxPMFR0ITtxu0cnpVSd5rTtT4PlneFn rSjz5A3ueyhZvToB4Za+wroZ/ei26rVU3EYchqsV2xi9GL2+5eN4vHk2UMJvXvhmWB ikV3ImmhL7wP2xCP0vmdv9FESQv/0JI4msXcPuXbngmDFV0+kpgkhqcuuwsgf6sFrs a0kyl7BpDlEeRW4CzybvKGyH9sgyfYZA2JtDHzDO6sB/UdqlmqRY42FwwTkWtHIfN8 hmOre//XZEAcQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH] 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: <20261020004119.106690-1-sj@kernel.org> References: <20261020004119.106690-1-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 20 Oct 2026 00:43:52 +0000 X-Mailing-List: damon@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > 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/20261020004119.1066= 90-1-sj@kernel.org?part=3D1