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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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 89C3420002 X-Stat-Signature: cy3xatoaegmk3w9d9untscpq1d81dduf X-HE-Tag: 1774759146-34004 X-HE-Meta: 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 SN1XqHet K5UWaj4m6dZ228T6lFOnQHRzwQznn4oV9ybbFhW9mtTXtjRaG7DAmuHlMM1+j69IeedZi787SENuczDTaXwsqJEoEC4r89YjsyIcC0obF+gM6ZMmU4HMlBOibufzCBijibYiDGs+JZkILurinToegqMrIOmqyPxHkA1dV7CKOB+1z4P9qKPlaspxfcdIPjXIyvR+rrGUXvSmlcxsP9y6ZoNTKFcRjh8vCk9WyJwMiYv76ncHINsIEqf9VAdfFRZVnLbEM7sWFHEQ4pPwJ49EzX1X39A== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 virtual 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 */ #ifdef CONFIG_NUMA +static bool invalid_mem_node(int nid) +{ + return nid < 0 || nid >= 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; + if (invalid_mem_node(goal->nid)) { + if (goal->metric == 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 == DAMOS_QUOTA_NODE_MEM_USED_BP) numerator = i.totalram - i.freeram; -- 2.47.3