1 files changed, 11 insertions, 2 deletions

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 3bebaed5021c..a2fecb1611cc 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -744,6 +744,17 @@ void __init mem_init(void)
 #ifdef CONFIG_FLATMEM
         BUG_ON(!mem_map);
 #endif
+        /*
+         * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to
+         * be done before free_all_bootmem(). Memblock use free low memory for
+         * temporary data (see find_range_array()) and for this purpose can use
+         * pages that was already passed to the buddy allocator, hence marked as
+         * not accessible in the page tables when compiled with
+         * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not
+         * important here.
+         */
+        set_highmem_pages_init();
+
         /* this will put all low memory onto the freelists */
         totalram_pages += free_all_bootmem();
 
@@ -755,8 +766,6 @@ void __init mem_init(void)
                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
                         reservedpages++;
 
-        set_highmem_pages_init();
-
         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;