2006-11-15 17:39:20

by OGAWA Hirofumi

Subject: [PATCH] Fix strange size check in __get_vm_area_node()

Recently, __get_vm_area_node() was changed like following

if (unlikely(!area))
return NULL;

- if (unlikely(!size)) {
- kfree (area);
+ if (unlikely(!size))
return NULL;
- }

It is leaking `area', also original code seems strange already.
Probably, we wanted to do this patch.

Signed-off-by: OGAWA Hirofumi <[email protected]>
---

mm/vmalloc.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff -puN mm/vmalloc.c~vmalloc-leak-fix mm/vmalloc.c
--- linux-2.6/mm/vmalloc.c~vmalloc-leak-fix 2006-11-16 00:41:49.000000000 +0900
+++ linux-2.6-hirofumi/mm/vmalloc.c 2006-11-16 00:41:49.000000000 +0900
@@ -181,14 +181,13 @@ static struct vm_struct *__get_vm_area_n
}
addr = ALIGN(start, align);
size = PAGE_ALIGN(size);
+ if (unlikely(!size))
+ return NULL;

area = kmalloc_node(sizeof(*area), gfp_mask & GFP_LEVEL_MASK, node);
if (unlikely(!area))
return NULL;

- if (unlikely(!size))
- return NULL;
-
/*
* We always allocate a guard page.
*/
_

--
OGAWA Hirofumi <[email protected]>

2006-11-15 17:51:07

by Eric Dumazet

Subject: Re: [PATCH] Fix strange size check in __get_vm_area_node()

On Wednesday 15 November 2006 18:39, OGAWA Hirofumi wrote:
> Recently, __get_vm_area_node() was changed like following
>
> if (unlikely(!area))
> return NULL;
>
> - if (unlikely(!size)) {
> - kfree (area);
> + if (unlikely(!size))
> return NULL;
> - }
>
> It is leaking `area', also original code seems strange already.
> Probably, we wanted to do this patch.
>

Indeed. I checked my original patch and it was correct. I dont know what
happened then...

http://lkml.org/lkml/2006/10/23/86

Eric