diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index a25d8beacc83..f51566316ba4 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1190,6 +1190,20 @@ static void __init map_mem(void)
 
 	/* map all the memory banks */
 	for_each_mem_range(i, &start, &end) {
+		/*
+		 * for_each_mem_range may return sub-page-aligned boundaries
+		 * after memblock_mark_nomap() splits regions at byte precision.
+		 * __create_pgd_mapping_locked aligns phys down to PAGE_MASK,
+		 * which could accidentally map no-map memory on the boundary.
+		 * Round the mappable range inward: start UP, end DOWN, so
+		 * that the mapped area never overlaps with adjacent no-map
+		 * regions. The cost is at most one page of unmapped gap at
+		 * each boundary.
+		 */
+		start = PAGE_ALIGN(start);
+		end = end & PAGE_MASK;
+		if (start >= end)
+			continue;
 		/*
 		 * The linear map must allow allocation tags reading/writing
 		 * if MTE is present. Otherwise, it has the same attributes as