diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index fd3da1dda1c9..ae4f7b5d7104 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -7,6 +7,7 @@
 #include <asm/page.h>
 #include <asm/page_types.h>
 #include <asm/sections.h>
+#include <asm/setup.h>
 #include <asm/system.h>
 #include <asm/tlbflush.h>
 
@@ -304,8 +305,23 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
 #endif
 
 #ifdef CONFIG_X86_64
-	if (!after_bootmem)
+	if (!after_bootmem && !start) {
+		pud_t *pud;
+		pmd_t *pmd;
+
 		mmu_cr4_features = read_cr4();
+
+		/*
+		 * _brk_end cannot change anymore, but it and _end may be
+		 * located on different 2M pages. cleanup_highmap(), however,
+		 * can only consider _end when it runs, so destroy any
+		 * mappings beyond _brk_end here.
+		 */
+		pud = pud_offset(pgd_offset_k(_brk_end), _brk_end);
+		pmd = pmd_offset(pud, _brk_end - 1);
+		while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1))
+			pmd_clear(pmd);
+	}
 #endif
 	__flush_tlb_all();