From mboxrd@z Thu Jan 1 00:00:00 1970 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: 8bit 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 address 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; + if (invalid_mem_node(goal->nid)) { + if (goal->metric == DAMOS_QUOTA_NODE_MEMCG_USED_BP) + return 0; + else /* DAMOS_QUOTA_NODE_MEM_FREE_BP */ + return 10000; + } + memcg = mem_cgroup_get_from_id(goal->memcg_id); if (!memcg) { if (goal->metric == DAMOS_QUOTA_NODE_MEMCG_USED_BP) -- 2.47.3