From nobody Thu Apr 2 15:35:56 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7AF0B2874E6; Sat, 28 Mar 2026 00:54:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774659256; cv=none; b=bzX6AmgCDpIbQHvwg3Tx+8d0wIkEExKK9FSYCjRGuTgtwRTOv1U+Oq/nSZgAuh+Qb+k0ZhmI7L1yGVL7LUteC6QHkXBo2eP++Tfqj+93Bjy0JVN3TWHwtFKdquyOeSYaF1385SEZZk/jFXJ0Kb/y7oZpbaDNvp6KG71d3+rO1tk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774659256; c=relaxed/simple; bh=xj+qGE0/+xoZp0bbzzefLJA/Ga+imeoh2utC1fQRZVY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oPASH+EWY23kY+oa48wB2rjup82nsRY0PVmGZ2zBGripeJcvfFgmPsBj1lkDT6Sw1Ub/O+SbMjSbFuy5JmX4wcyJ9fLx6+XvSR20N+QmAx5FmYvwAj7Xq/aXzcwam/SlvldVwvkt01vGSVpWrB+jGBJ2tg00IRnQfFAI6cGqO7Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KbxFGJ/1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KbxFGJ/1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E0FE2C2BCB1; Sat, 28 Mar 2026 00:54:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774659256; bh=xj+qGE0/+xoZp0bbzzefLJA/Ga+imeoh2utC1fQRZVY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KbxFGJ/1VvEfifuvXF9eb1wOC09YVBuwaq71eXVjuyBkPpR+mxbz473h7tddXueDU DsMDGMk+EcOvrQa3ni0cXa602tIVOYGiRHUdJEPJ6XQKJxQ+BVbuTDhmBsej/Evzlv u+aijzLWeUhVf+Iujs22FYhn3bxDGelB5WdaDvOY7MdEIxLv3YVPBTzNmyuNQpOwy8 Tw/l6titFFHfPgyHP3uCTo+jDEwQ0xH73xyrEozwVx5iCcS6Jz6nfBRtZY1NUKbGvx qAkrqSJLKIn9NO50PmECP6W+VsWhHRf1dfEVgbk93UVvJt41iRYcclgGOX3RA6DXCV prv6UP89Wp3CQ== From: SeongJae Park To: Cc: SeongJae Park , "# 6 . 19 . x" , Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 2/2] mm/damon/core: validate damos_quota_goal->nid for node_memcg_{used,free}_bp Date: Fri, 27 Mar 2026 17:54:10 -0700 Message-ID: <20260328005412.7606-3-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260328005412.7606-1-sj@kernel.org> References: <20260328005412.7606-1-sj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Users can set damos_quota_goal->nid with arbitrary value for node_memcg_{used,free}_bp. But DAMON core is using those for NODE-DATA() without a validation of the value. This can result in out of bounds memory access. The issue can actually triggered using DAMON user-space tool (damo), like below. $ sudo mkdir /sys/fs/cgroup/foo $ sudo ./damo start --damos_action stat --damos_quota_interval 1s \ --damos_quota_goal node_memcg_used_bp 50% -1 /foo $ sudo dmseg [...] [ 524.181426] Unable to handle kernel paging request at virtual addres= s 0000000000002c00 Fix this issue by adding the validation of the given node id. If an invalid node id is given, it returns 0% for used memory ratio, and 100% for free memory ratio. Fixes: b74a120bcf50 ("mm/damon/core: implement DAMOS_QUOTA_NODE_MEMCG_USED_= BP") Cc: # 6.19.x Signed-off-by: SeongJae Park --- mm/damon/core.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/damon/core.c b/mm/damon/core.c index 9a848d7647ef..3298ee8d8f64 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -2251,6 +2251,13 @@ static unsigned long damos_get_node_memcg_used_bp( unsigned long used_pages, numerator; struct sysinfo i; =20 + if (invalid_mem_node(goal->nid)) { + if (goal->metric =3D=3D DAMOS_QUOTA_NODE_MEMCG_USED_BP) + return 0; + else /* DAMOS_QUOTA_NODE_MEM_FREE_BP */ + return 10000; + } + memcg =3D mem_cgroup_get_from_id(goal->memcg_id); if (!memcg) { if (goal->metric =3D=3D DAMOS_QUOTA_NODE_MEMCG_USED_BP) --=20 2.47.3