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b=GLnwvxPgM6IFQbMezL9MtZrDzM1hsTBXxvfaI+sjUez3ue0H+ua8UG77/uPyY1Uf+ iFRLS6lpqX2hRyDdvECbFSfCFbByNU3SAMqmzR493pyBhuR+RShpC0IGCSdiMW8LVE xiYytcRiQBY//nE6dA9uJ1o9RowTcM8AA3/sUFWEFeSH/q3fzSQntxW7fBVEO+3Yec g2pz0AiRXp5FHCkzoZ6nfOsFW+sYgwFAlxc9FQZ6j2r8r/iO/hTIrchcsWrN2jrfmW qrs/UuCYcNs9xARygbuqWqVVGLbccGLhkZMQ/KpunO5UKhTqEPm6Fqg801C87yyQS5 HYeZ8qPSg6TvA== From: SeongJae Park To: Josh Law Cc: SeongJae Park , Andrew Morton , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2] mm/damon/core: validate goal nid before accessing node data Date: Wed, 25 Mar 2026 17:35:14 -0700 Message-ID: <20260326003515.77311-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260325155221.202700-1-objecting@objecting.org> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: 2D79B40003 X-Stat-Signature: ii3t6sbhqqiy1xccze3jxznst8tcrw56 X-Rspamd-Server: rspam06 X-HE-Tag: 1774485324-869668 X-HE-Meta: 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 antdmNyf 6i2l0LCsbYUP/5PyC4LGrug4hUClaBEAGwblYZihsjPn8vBHXdmwP8paw5yV57KVlvuGW7K/egaHRWqIP4MgLz5SLQHlRWVgtCspmb14xfIB1Ms7QGNLhgmwkA3gu5qlmtB4mF2n1YoZaen34EcEN4QY7V7WUR/tkQv2aYWAX+SPZTqGzGPs+vxxvti419vMLNx4UiawKrOgBbo/5z+XU2UOPpAg2Pm528m0JWgV8cuG/UIxujrwOljpXZjydJd4YAXYvFQvkVTC213d+Bevvpo/8TtxxHfSVj/dv Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, 25 Mar 2026 15:52:21 +0000 Josh Law wrote: No rush, Josh. As I mentioned before, please give about a day after the last comment on the previous version of the patch, before posting a new version. That could help giving enough time for others to add their important findings. > damos_get_node_mem_bp() and damos_get_node_memcg_used_bp() pass > goal->nid directly to si_meminfo_node() and NODE_DATA() without > checking that it refers to a valid, online NUMA node. Since s/online/memory/ ? > goal->nid is set from userspace via sysfs with no validation, a > negative or out-of-range value causes an out-of-bounds access in > NODE_DATA(), and a valid but offline node gives undefined results. > > Add bounds and node_state(N_MEMORY) checks before using the nid, > consistent with damon_migrate_pages(). > > Fixes: 0e1c773b501f ("mm/damon/core: introduce damos quota goal metrics for memory node utilization") > Cc: stable@vger.kernel.org > Signed-off-by: Josh Law > --- As I also previously mentioned, please add changelog here. > mm/damon/core.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/mm/damon/core.c b/mm/damon/core.c > index 59b709f04975..112125b635d7 100644 > --- a/mm/damon/core.c > +++ b/mm/damon/core.c > @@ -2227,6 +2227,10 @@ static __kernel_ulong_t damos_get_node_mem_bp( > struct sysinfo i; > __kernel_ulong_t numerator; > > + if (goal->nid < 0 || goal->nid >= MAX_NUMNODES || > + !node_state(goal->nid, N_MEMORY)) > + return 0; > + > si_meminfo_node(&i, goal->nid); > if (goal->metric == DAMOS_QUOTA_NODE_MEM_USED_BP) > numerator = i.totalram - i.freeram; > @@ -2243,6 +2247,10 @@ static unsigned long damos_get_node_memcg_used_bp( > unsigned long used_pages, numerator; > struct sysinfo i; > > + if (goal->nid < 0 || goal->nid >= MAX_NUMNODES || > + !node_state(goal->nid, N_MEMORY)) > + return 0; > + > memcg = mem_cgroup_get_from_id(goal->memcg_id); > if (!memcg) { > if (goal->metric == DAMOS_QUOTA_NODE_MEMCG_USED_BP) > -- > 2.34.1 I will add more comments as a reply to sashiko comment. Thanks, SJ [...]