mm-damon-core-validate-damos_quota_goal-nid-for-node_memcg_usedfree_bp.patch removed from -mm tree

The quilt patch titled

     Subject: mm/damon/core: validate damos_quota_goal->nid for node_memcg_{used,free}_bp

has been removed from the -mm tree. Its filename was
mm-damon-core-validate-damos_quota_goal-nid-for-node_memcg_usedfree_bp.patch

This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: SeongJae Park <[email protected]>
Subject: mm/damon/core: validate damos_quota_goal->nid for node_memcg_{used,free}_bp
Date: Sat, 28 Mar 2026 21:39:00 -0700

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.

---

 mm/damon/core.c |    7 +++++++
 1 file changed, 7 insertions(+)

@@ -2251,6 +2251,13 @@ static unsigned long damos_get_node_memc
 	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_MEMCG_FREE_BP */
+			return 10000;
+	}
+
 	memcg = mem_cgroup_get_from_id(goal->memcg_id);
 	if (!memcg) {
 		if (goal->metric == DAMOS_QUOTA_NODE_MEMCG_USED_BP)

_

Patches currently in -mm which might be from [email protected] are

mm-damon-core-disallow-time-quota-setting-zero-esz.patch mm-damon-core-disallow-non-power-of-two-min_region_sz-on-damon_start.patch