Merge tag 'fixes-2024-12-06' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock

Pull memblock fixes from Mike Rapoport:
 "Restore check for node validity in arch_numa.

  The rework of NUMA initialization in arch_numa dropped a check that
  refused to accept configurations with invalid node IDs.

  Restore that check to ensure that when firmware passes invalid nodes,
  such configuration is rejected and kernel gracefully falls back to
  dummy NUMA"

* tag 'fixes-2024-12-06' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
  arch_numa: Restore nid checks before registering a memblock with a node
  memblock: allow zero threshold in validate_numa_converage()

Author: torvalds

drivers/base/arch_numa.c

@@ -208,6 +208,10 @@ static int __init numa_register_nodes(void)
 {
 	int nid;
 
+	/* Check the validity of the memblock/node mapping */
+	if (!memblock_validate_numa_coverage(0))
+		return -EINVAL;
+
 	/* Finally register nodes. */
 	for_each_node_mask(nid, numa_nodes_parsed) {
 		unsigned long start_pfn, end_pfn;

mm/memblock.c

@@ -735,7 +735,7 @@ int __init_memblock memblock_add(phys_addr_t base, phys_addr_t size)
 /**
  * memblock_validate_numa_coverage - check if amount of memory with
  * no node ID assigned is less than a threshold
- * @threshold_bytes: maximal number of pages that can have unassigned node
+ * @threshold_bytes: maximal memory size that can have unassigned node
  * ID (in bytes).
  *
  * A buggy firmware may report memory that does not belong to any node.
@@ -755,7 +755,7 @@ bool __init_memblock memblock_validate_numa_coverage(unsigned long threshold_byt
 			nr_pages += end_pfn - start_pfn;
 	}
 
-	if ((nr_pages << PAGE_SHIFT) >= threshold_bytes) {
+	if ((nr_pages << PAGE_SHIFT) > threshold_bytes) {
 		mem_size_mb = memblock_phys_mem_size() >> 20;
 		pr_err("NUMA: no nodes coverage for %luMB of %luMB RAM\n",
 		       (nr_pages << PAGE_SHIFT) >> 20, mem_size_mb);