On Fri, 30 Aug 2019 12:57:16 +0900 Austin Kim <austindh....@gmail.com> wrote:
> If !area->pages statement is true where memory allocation fails,
> area is freed.
>
> In this case 'area->pages = pages' should not executed.
> So move 'area->pages = pages' after if statement.
>
> ...
>
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2416,13 +2416,15 @@ static void *__vmalloc_area_node(struct vm_struct
> *area, gfp_t gfp_mask,
> } else {
> pages = kmalloc_node(array_size, nested_gfp, node);
> }
> - area->pages = pages;
> - if (!area->pages) {
> +
> + if (!pages) {
> remove_vm_area(area->addr);
> kfree(area);
> return NULL;
> }
>
> + area->pages = pages;
> +
> for (i = 0; i < area->nr_pages; i++) {
> struct page *page;
>
Fair enough. But we can/should also do this?
--- a/mm/vmalloc.c~mm-vmalloc-move-area-pages-after-if-statement-fix
+++ a/mm/vmalloc.c
@@ -2409,7 +2409,6 @@ static void *__vmalloc_area_node(struct
nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
array_size = (nr_pages * sizeof(struct page *));
- area->nr_pages = nr_pages;
/* Please note that the recursion is strictly bounded. */
if (array_size > PAGE_SIZE) {
pages = __vmalloc_node(array_size, 1, nested_gfp|highmem_mask,
@@ -2425,6 +2424,7 @@ static void *__vmalloc_area_node(struct
}
area->pages = pages;
+ area->nr_pages = nr_pages;
for (i = 0; i < area->nr_pages; i++) {
struct page *page;
_
