[PATCH 1/2] mm: update the memmap stat before page is freed

[Pasha Tatashin]

It is more logical to update the stat before the page is freed, to avoid
use after free scenarios.

Fixes: 15995a352474 ("mm: report per-page metadata information")
Signed-off-by: Pasha Tatashin <pasha.tatas...@soleen.com>
---
 mm/hugetlb_vmemmap.c | 4 ++--
 mm/page_ext.c        | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 829112b0a914..fa83a7b38199 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -185,11 +185,11 @@ static int vmemmap_remap_range(unsigned long start, 
unsigned long end,
 static inline void free_vmemmap_page(struct page *page)
 {
        if (PageReserved(page)) {
-               free_bootmem_page(page);
                mod_node_page_state(page_pgdat(page), NR_MEMMAP_BOOT, -1);
+               free_bootmem_page(page);
        } else {
-               __free_page(page);
                mod_node_page_state(page_pgdat(page), NR_MEMMAP, -1);
+               __free_page(page);
        }
 }
 
diff --git a/mm/page_ext.c b/mm/page_ext.c
index c191e490c401..962d45eee1f8 100644
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -330,18 +330,18 @@ static void free_page_ext(void *addr)
        if (is_vmalloc_addr(addr)) {
                page = vmalloc_to_page(addr);
                pgdat = page_pgdat(page);
+               mod_node_page_state(pgdat, NR_MEMMAP,
+                                   -1L * (DIV_ROUND_UP(table_size, 
PAGE_SIZE)));
                vfree(addr);
        } else {
                page = virt_to_page(addr);
                pgdat = page_pgdat(page);
+               mod_node_page_state(pgdat, NR_MEMMAP,
+                                   -1L * (DIV_ROUND_UP(table_size, 
PAGE_SIZE)));
                BUG_ON(PageReserved(page));
                kmemleak_free(addr);
                free_pages_exact(addr, table_size);
        }
-
-       mod_node_page_state(pgdat, NR_MEMMAP,
-                           -1L * (DIV_ROUND_UP(table_size, PAGE_SIZE)));
-
 }
 
 static void __free_page_ext(unsigned long pfn)
-- 
2.46.0.76.ge559c4bf1a-goog