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=1794090547; b=Jx4ahOiRCvQaHO0x2LXMUSDQLnzQEtA/G1em8DHps6UAb3QDg1uljPWazw1OAqlR0TpZ /7LKEqH6RuW/mLBA3YEBU2vKZUFxfYFcHftHXAAAM/TzrArxll++5LohRaYMXYhTLEBt6 DZseXqB2kv0FNYtN/dtlD57CU4kiK7j/uvUnyZvp8r3dfG4CVG7O34V7vs/YO0IsnQtZx fRBEYQQh4+kPsjX46vMFNUiVDvsarkPaQnhBnrk+wwRzqUD1ULyWMf6A3EOqpANUNm3hO LovRL8AcPw5ppcS2iO9eq9VhL7UAu6Ovrjx/UO4cqeechQF257O50FAYAAV7YY5FEvg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794090547; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=d8rzaLmod9hiDF4G+MlCbWdWyTmETfp82LhWWlg0nuY=; b=Cofp7CkLvC4OXmEEVrg+rcrX67Y+uYJ8dyBaHwFA2yhdfluE8umQNq6ha0K7iKG+pS0/ RImaIl52LVfnk/kcIzXz8nccQ8LCzZz/DiO2r7qscrRIeKpbyTyf6KeKgiJglJEoTY3NT ElsAWN/Ap9oxk/ekOVaXvPyG0xxa5JTipFU9TCbq3e1HWtTzJ+va7406RpcrY2WEG1wwL PmL9ggopPkRm6/XB1VkOdQ6IRrZolhTmU18vSJJLLO97i+U5THjNmll5OaCOFlphAUV1j hMCAy2Rq+uovLhI9yPChxOMLI87gmbQpvAwi5IR/gHnUZCr8swFpKoYugqObh/R1MXg== 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=XpZSAkW9; 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 884A6606A326 for ; Sat, 7 Nov 2026 22:29:07 +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=XpZSAkW9 Received: by smtp.kernel.org (Postfix) with ESMTPSA id F05F11F0089F; Sat, 7 Nov 2026 22:29:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794090547; bh=d8rzaLmod9hiDF4G+MlCbWdWyTmETfp82LhWWlg0nuY=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=XpZSAkW9ffTGXQU6zQfgVLdCzZSKokQhcVG+oYdAEXqdrHeKxP38gHWYXl3bGZ6LC SYRAMwpci8aXJO6EFtU+WpQG0RBvZPKQzdpUF5/IElFY9IYBdIuK99IZpbrj7jPUFL kTne8RE1BWplEhFA7nWTBKt1pj/h1HTbelIg7YftdBFS/8qzDn2rCri6LBOXPfLV6x kKQ1FTgpka6LHXtA6Yu8mWamOx62gM0R09E6pvgDFesUZW4GrYzhlrlxTd1g2S1HIQ jvNLKh6vUhu1refL/O53044EcdtmwzBS9rMltGggbEbhxyZ41B2lC3VaoWTu+GPS9L QHGCHcKIa8FQQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC 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: <20261107222202.331476-3-sj@kernel.org> References: <20261107222202.331476-1-sj@kernel.org> <20261107222202.331476-3-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sat, 07 Nov 2026 22:29:06 +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/20261107222202.3314= 76-1-sj@kernel.org?part=3D2