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=1794169361; b=DueBlpWx19MWp9+X1/cuyzs5CRCtcBCNtUUKkobNAIdl5xxGqlpI9M6w+WhAmHSAFRya W6iZ5Ea7GntRulcjOGLlJaqkktxJfe5SUAsbbsZNysdF9ojJ0IaflMMleSeoIAStnGTTo lgejE0a6i4SyRhHVfvRsESn4DclR98ugh4brqfT2BKH4G5WxvbSh8+LIKBSgVQ8YxShd7 df6isZY62ZvCSqNh8Ke2TPBm/ZdpTkqD8Zq2ElnSyFntOp5xeJjz11/QrFH0BvCiHHc4f zNSXEMJFoJ9a4JlRNQy+AYVwgknxRtEiUsZdKsegI2b5piqH7OvXPLdwON3Dym/u+eA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794169361; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=E+p18EIROBMxVD0jqjnHNJu4f/pkCw6LWfOkniC3yrY=; b=HgFWnimZZ9ViycFtXVe35TDX420vXSoNbvVBx28TFe95rxICgDN3ok8Hi77qFiioZnx7 ltp4eenlSSG2Bpc+ClKrlB54bDkTUQuQG7a1mAvCPYmXugeCW3d9j/1WgTbBTi7UPeC/V ckDtFi5C5LJKqdbToFxuD6gaFEU4IDdnw02cN8rQfRadhSQ8TvR4fr/JWezr+w2sMMAzo 8SGb7HpMv3z/eZJHNJcBH1eIyTxZBpwR1sL/CcnM1rLRprQVXazZ6vL3osQTd66Sb2Uo7 YuUBu8u5OhmlCY0A9w8SVPRWInBOTsupY1Bm/ntx6nnxhpi7VSYgz5fhbLVR3zY/2Vw== 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=oIIjMVmJ; 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 EFBDD606A9E4 for ; Sun, 8 Nov 2026 20:22:40 +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=oIIjMVmJ Received: by smtp.kernel.org (Postfix) with ESMTPSA id B24A51F008A2; Sun, 8 Nov 2026 20:22:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794169360; bh=E+p18EIROBMxVD0jqjnHNJu4f/pkCw6LWfOkniC3yrY=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=oIIjMVmJ0IoLocPRkq8vYnTt3TjVbqCsmuDCGAreDvYqMLV4m/WiPcebiOaYIxEYG +qWEJ0GashwjWIjx3AaFv0CSXCszpchPN9OnVscgMqtT+wh00bjFtfxNM6cMDp1vym NeKQ2HwC+dXegk34jcM1vXA67y+dDoIdcL5x41syTCBjXzO/bmFKn45U+1UESQpkZS 5nFypZiaIVzCcmv4IUtQQxKFSm76IcI79OGoZZRyBxseGHkfBAV2aQIVgbK8IphzgS OjjY5a5M5Zlfeb/e+2PEezklAdqNnstc+Rgx4xhb0GdREvo385L7SiaI4i3iYPqJb7 hNBdzN0Nr/orA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 6.6.y 2/3] 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: <20261108201456.116824-3-sj@kernel.org> References: <20261108201456.116824-1-sj@kernel.org> <20261108201456.116824-3-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sun, 08 Nov 2026 20:22:40 +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/20261108201456.1168= 24-1-sj@kernel.org?part=3D2