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=1794088412; b=ZxCXWncoLLxbY/0Rv6no/+N947aUcaPsqWnO98GJGUGeL4Vh0LO9zAL4GIt5N3XVjPNP zGrFCxDyDWzag9yWtmha1+4zfV+/+J8KyI+2VEWMcE01f0RWWpy0dWQ95KiLdHx+jww6D 1c9ZkEl1cCWXd0845olDp++rRLtALckg5fFHCCpmoJ5+dl2o8RonRqitkD+su7WE2NsgF 2YbwyrEg3aszTaHxhq21r8a6upNAE2HMBU7b59N+A3YN9DM602Fu2JBFgjK2BB/tRm0Ul xLkDTieUTuSH+PRISM425ONUz3Co65ye5ADgkk/yIaCFJh6/0JJfTRBIJnYK2FbkInQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794088412; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=8ySQyWpzVUQwlPK0mIdtUAo/slZnp9cE5tLXFw3xRes=; b=3E/BOgpOzWC+U+qkivXGb2UV88Wa9NG50svo4I8BtwGjVP9LY+OMyld/I+kcJvgDaXgs Mz3dUTb+XggVCg6uxxxakaI2PciHy1806t1Dr+PCZr5i1Na9YgvAw2d4Z9eCWRj4mZpja PvG0TnexeBoUZgoLRNC9AX5BM7rH0qUza7+BN/6PWun5S4GBzNAQVkNdA8iamclgbKfAH SxOLC16353aLo0F2vOX/sLysYPzyuvCMOCdaCoMgmH6NVt2D0vHiZEvcNVNFNu4c4kbUa gdS+Z0AiY1KIMoMYEiAjH6blnydKsUBGLaPmKxEh48jvuVFY/BAjkRiOneNstPtPq/w== 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=SIop3eDl; 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 71073606A32D for ; Sat, 7 Nov 2026 21:53:32 +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=SIop3eDl Received: by smtp.kernel.org (Postfix) with ESMTPSA id 327581F0089F; Sat, 7 Nov 2026 21:53:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794088412; bh=8ySQyWpzVUQwlPK0mIdtUAo/slZnp9cE5tLXFw3xRes=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=SIop3eDlbHiE4xK7e3Bh2YpUI8aRYtdFD6wP43zdNtmf+eISb7qk49hY5slMHplN0 SUQJV0XlExofdGeu1ayI3scIe6gvpyh7lCvQk17h217ugFJ3TsC+s6vnnhU9UT1IOQ gc1MsrA8eTYduMAlDok+1ac+CRIksLfaRH0byRdtvIns3SoFH8a85prlVkIlyeq0pp elUNooxCOS78yKq10XdwePVJP1SRUb57/UPAjPXUPCJLXTYxP1hquP+iVJu0k5ZuZz vGYjHtPBsqhQPfSb8sbPaeQ1OtZeUJXx4TMRF0Fc16c/n8WRoZCrjaWwfcOJNR1n/G rAdHQfIAlSAzQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC 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: <20261107214525.304638-5-sj@kernel.org> References: <20261107214525.304638-1-sj@kernel.org> <20261107214525.304638-5-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sat, 07 Nov 2026 21:53:31 +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/20261107214525.3046= 38-1-sj@kernel.org?part=3D4