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SubjectRe: [PATCH] mm/vmalloc: move 'area->pages' after if statement
2019년 8월 31일 (토) 오전 5:50, Andrew Morton <akpm@linux-foundation.org>님이 작성:
>
> On Fri, 30 Aug 2019 12:57:16 +0900 Austin Kim <austindh.kim@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?

I agreed since it is the same treatment.
Thanks for feedback.

>
> --- 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;
> _
>

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