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=1794167935; b=I9/AXfcVj+3NhyvnSZNKyeOHM1169RkzpB31Cj7v8FXvqzB98Tj7E6yWxDg0xov5ghvV gsTVsCA19PyQsT6GqNPOh/6jpCIjc6ldAngGvxulzxM+toaU+tLfmFDriwXPUbpE22xL8 wiBZPKAl4IWbgJ3rXlh3K1Wxyb2dVECZaS7zD+4k8/KFyWg/XgcOudp3g+750WgdTcpLw oF0aIIbiDuIfK74Mg/yze1r6x60YmAWRCAObiciu1btuR55PiPeVoudydZspCU7LPP/xe lsaFfMFPYE+id1+Ihr1GAjZY8m8G+YnWEPcIfbjQJXjlA4vhGpmBVZS2ow8erff6bxg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794167935; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=OHdC0GgEhyrosirHNB/j9T8So70Qs+7SiSlEMgyb4uI=; b=X3g5lVOagBdtWfBhZw0p4opt84J3fVH0n4zy6GZ19c3okoavnJN3LiQULJdRCM8vgPbQ ASYrIahwUWjBhmzuw8klR2x8KdheuqC2u7m3F5oK4etPn1KG7q4qlf23EqTzTeWvsr01S vrR3fkc2qh8k0XlKEPiwvkWZe0gShnMCLLpgkzUtxEpCgN1ogSQZxLjXLV/5wSl27QGIb YsJLNvJ2xWyIyRz4WwfVLo/eEi/aIdQ4G2fXrBDRuMOMPjjKB0CdD2C5BHRSP7rYqkFXM GlVfyMbOjnFo+9dfFUfomSzOzITVCL/2QeCGPs8Cz7/Cg1xK2GBU67ydkl8jVx7Dz8w== 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=fG38dylr; 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 59578606A31C for ; Sun, 8 Nov 2026 19:58:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=fG38dylr Received: by smtp.kernel.org (Postfix) with ESMTPSA id D208B1F0089F; Sun, 8 Nov 2026 19:58:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794167935; bh=OHdC0GgEhyrosirHNB/j9T8So70Qs+7SiSlEMgyb4uI=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=fG38dylr9Hy1btz5PvAxrRAt/orWcJxUM2voNaet6bOKkGuuuOTUBnMBgArAckq8U tTeF98Jrcfa+2HS05hjKOQNrbdTQPfiW2i+sU1DiLaNMl1qbixrVsxq2HBvqFDE9BR ///7R0lL+dn7iXebZywDkgSgniNr3BQaGSZOkpdgL+Bu9fUVFQt+IUFz5R0w7az1nP /VUyesUkBgR5+VWHEc3QR93MPx6EaNUqA/M/AOZRugGXMCZmQRJGoSkHJIdXB1P5Zm nnfXfM9o6ufbENK8B3iXmmAnoJwreDaSqPBctV/VSdZHfDZhLn+TCIbxpFLwaIZU3c uqZzfndzwXu6Q== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 6.12.y 4/5] 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: <20261108195145.115792-5-sj@kernel.org> References: <20261108195145.115792-1-sj@kernel.org> <20261108195145.115792-5-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sun, 08 Nov 2026 19:58:54 +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 > Link: https://lore.kernel.org/20261020004119.106690-1-sj@kernel.org > Link: https://lore.kernel.org/20260801203121.117449-1-sj@kernel.org [1] > Fixes: ab9bda001b68 ("mm/damon/core: introduce address range type damos f= ilter") > Signed-off-by: SJ Park > Signed-off-by: Andrew Morton > Cc: # 6.6.x > (cherry picked from commit bbeec2d8324d7aac438bb12dd2d22b184e0a8d43) > Signed-off-by: SJ Park Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261108195145.1157= 92-1-sj@kernel.org?part=3D4