[PATCH] mm: fix oom roll-back of __vmalloc_area_node

__vunmap must not rely on area->nr_pages when picking the release methode
for area->pages.  It may be too small when __vmalloc_area_node failed early
due to lacking memory.  Instead, use a flag in vmstruct to differentiate.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 5 insertions, 3 deletions

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index f6024ab4eff..71b6363caaa 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -11,6 +11,7 @@ struct vm_area_struct;
 #define VM_ALLOC        0x00000002      /* vmalloc() */
 #define VM_MAP          0x00000004      /* vmap()ed pages */
 #define VM_USERMAP      0x00000008      /* suitable for remap_vmalloc_range */
+#define VM_VPAGES       0x00000010      /* buffer for pages was vmalloc'ed */
 /* bits [20..32] reserved for arch specific ioremap internals */
 
 /*
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 7b450798b45..266162d2ba2 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -340,7 +340,7 @@ void __vunmap(void *addr, int deallocate_pages)
                         __free_page(area->pages[i]);
                 }
 
-                if (area->nr_pages > PAGE_SIZE/sizeof(struct page *))
+                if (area->flags & VM_VPAGES)
                         vfree(area->pages);
                 else
                         kfree(area->pages);
@@ -427,9 +427,10 @@ void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 
         area->nr_pages = nr_pages;
         /* Please note that the recursion is strictly bounded. */
-        if (array_size > PAGE_SIZE)
+        if (array_size > PAGE_SIZE) {
                 pages = __vmalloc_node(array_size, gfp_mask, PAGE_KERNEL, node);
-        else
+                area->flags |= VM_VPAGES;
+        } else
                 pages = kmalloc_node(array_size, (gfp_mask & ~__GFP_HIGHMEM), node);
         area->pages = pages;
         if (!area->pages) {