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=1794166269; b=DwDOnhhuULspQeywsNgdD86nbx4Bj2OZVqz6arNoZjwqj1x7syYspW7qCQblkkvePTUU F3WK9DWGprKFyMXPkuVIiph6z0F/qJnlr7P+0HHPacRCZe+suGhmZfFJtsvWQAy81HNuX VMgUv9ED+MzcybbSyElBt6YmNl3ZMB8PgY0xye3X59BAC4kR+3O/5DGRp/8jn+rERQTJy RRP3F0M+pcYdadkCOMXbJuQKteL9BgAbN/fJXLQITmdptF1egZ68AUQsJp0+R48GufAO6 elPooX7CZb2ixnjJ0s+JmscPzuxIb/nzQKrDxr5SN/AR6zxB+OUOpeXTn4tfd8b0h3g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794166269; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=rAlcP9dw2LpkFO9MDMT2YuT8skYn6YuLlzleJQ5ybGA=; b=RN7FYo8ac4B6DIFLstR0SLhQqGhxNKOMoA1q5/eNvIo1pJuYAg2OjBjBz+kWrmDaXkfi Sj/BIwZWyj2QjzYtUt0NldFDpC0RPfVD3Ta5y+c8+1LDm8nXZR0dZhNl+Aa+kcZp+1Aki swwAkbaH5R+ymKFlM1/YfJjVDxuKAQtUv1kxDcphzViyUwOWmB7O4UTCk52qXccvhw46U oTybORsrAxxqza+JbvVPZqYIP/LN1Vs78JBRbFx20e8Vw2qoFrQM7cE3OBFMcURT2QHub EZDamS8w0Gv/teSTzoSGyBxCv3Raz/zgHGqOUmEcyeXkOKReVgMPUek1fyUEVYcgLEQ== 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=NR+T37B2; 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 DAEE1606A321 for ; Sun, 8 Nov 2026 19:31:08 +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=NR+T37B2 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40B611F0089F; Sun, 8 Nov 2026 19:31:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794166268; bh=rAlcP9dw2LpkFO9MDMT2YuT8skYn6YuLlzleJQ5ybGA=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=NR+T37B2kRHVYsIkAsZJKUBrMyXlNBk468m4f020t1kCwwJl3iOY7rtUsYOfAk4Nt r8DLLBcEO9kw7owAAV/gvjyGKj9s4r/Pemh80MWs62OukDH+YrbEYw3q13GBA6SbeZ pr8TeE1DPf1QbgAH6u8xBdTYsrfDTqlPho1jNV/rSDhcMbrp0iS4T0tYOdOSPu+uS0 Ioi/pNv+awRZBg1Fuqb+J7cbqxBBL8M+gvRfBQWZLMO7UUF22Km9dwXkja+Z9gjTZH qYT08+mUwvG8BGBE7Qz20HNJ350dlTkgmAE8p+/C+RhEGYxaxNkpSUoWlXw8fpDqUy NY44UDJjAz9Xg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 6.18.y 5/5] 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: <20261108192221.114362-6-sj@kernel.org> References: <20261108192221.114362-1-sj@kernel.org> <20261108192221.114362-6-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sun, 08 Nov 2026 19:31:07 +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/20261108192221.1143= 62-1-sj@kernel.org?part=3D5