From nobody Mon Apr 6 09:08:56 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 97EC01F91D6; Sun, 29 Mar 2026 04:39:05 +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=1774759145; cv=none; b=Eam+E5TDBk2mpQSXlNWOxjTKC0czX25Wtud9FbtfcMLTtjr6ONZOblnq7NfZSgqkMRDw/hGO5AsFWsn8P0M8TbiTurLd04rB/vBeluGXm/2Ch3hKdyuDD1RuZ/O09puub8Yn0oatfEzJAqWYLSwFVsWb5YBIrhpyhkzkD9aBLNQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774759145; c=relaxed/simple; bh=EHLWGxW7vsnb0JYbS1TWbmzJf4dzLg0vok6TKbBxOAM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=okJQdnsikSePL1/DE1FTneT4+C/NCgKJA+8xJJt76NGixGEBOLKL1GspFr5OV1hOD5cR/ZdhUR1CT1+szKQ/YXZA4ckCJih0zp8O4VE8yZaFZbW/ugy0jIBxN4gIyP6GYa547bGvTtT/TwTIcmIXd2x8JFe7v3kGlMQA92WTsaA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cRiQBnpb; 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="cRiQBnpb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4ED03C2BCB2; Sun, 29 Mar 2026 04:39:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774759145; bh=EHLWGxW7vsnb0JYbS1TWbmzJf4dzLg0vok6TKbBxOAM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cRiQBnpb3XEA6rAA2mvK45qT/sGo9EjJNFM+Sm+SPUYiEqKvL35//LdstMht86/HP DLPR+lCWNEoMOkaD8BQJs5tOqjukX8qhEowT/b8epdtLSnHpTVscHbGIuCfwHWy3W7 D9heDL3idd2cC8nXU378P2ejN4NPzWPl9pgzFKI4MTppraMimCoCQWgVqb6jWCUl9a XPif1dFwd/SWoFae3gIFFnpGLade3TPKuyFVvUoxBtvr8y1J6yP/H/Go0cfLbGbjGc KGlLq/4ZsGr9wBGXwAyTeUZoOWHLRTx1utPGe54LAxKznfXrv6cRfDupL+EzH5Si+y 8DYVHH6JP/eRQ== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , "# 6 . 16 . x" , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 1/2] mm/damon/core: validate damos_quota_goal->nid for node_mem_{used,free}_bp Date: Sat, 28 Mar 2026 21:38:59 -0700 Message-ID: <20260329043902.46163-2-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260329043902.46163-1-sj@kernel.org> References: <20260329043902.46163-1-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_mem_{used,free}_bp. But DAMON core is using those for si_meminfo_node() without the 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 ./damo start --damos_action stat \ --damos_quota_goal node_mem_used_bp 50% -1 \ --damos_quota_interval 1s $ sudo dmesg [...] [ 65.565986] Unable to handle kernel NULL pointer dereference at virt= ual address 0000000000000098 Fix this issue by adding the validation of the given node. If an invalid node id is given, it returns 0% for used memory ratio, and 100% for free memory ratio. Fixes: 0e1c773b501f ("mm/damon/core: introduce damos quota goal metrics for= memory node utilization") Cc: # 6.16.x Signed-off-by: SeongJae Park --- mm/damon/core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/mm/damon/core.c b/mm/damon/core.c index ddabb93f2377..9a848d7647ef 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -2217,12 +2217,24 @@ static inline u64 damos_get_some_mem_psi_total(void) #endif /* CONFIG_PSI */ =20 #ifdef CONFIG_NUMA +static bool invalid_mem_node(int nid) +{ + return nid < 0 || nid >=3D MAX_NUMNODES || !node_state(nid, N_MEMORY); +} + static __kernel_ulong_t damos_get_node_mem_bp( struct damos_quota_goal *goal) { struct sysinfo i; __kernel_ulong_t numerator; =20 + if (invalid_mem_node(goal->nid)) { + if (goal->metric =3D=3D DAMOS_QUOTA_NODE_MEM_USED_BP) + return 0; + else /* DAMOS_QUOTA_NODE_MEM_FREE_BP */ + return 10000; + } + si_meminfo_node(&i, goal->nid); if (goal->metric =3D=3D DAMOS_QUOTA_NODE_MEM_USED_BP) numerator =3D i.totalram - i.freeram; --=20 2.47.3