diff mbox series

slub: Add back check for free nonslab objects

Message ID 20210927020922.87449-1-wangkefeng.wang@huawei.com (mailing list archive)
State New
Headers show
Series slub: Add back check for free nonslab objects | expand

Commit Message

Kefeng Wang Sept. 27, 2021, 2:09 a.m. UTC
After commit ("f227f0faf63b slub: fix unreclaimable slab stat for bulk
free"), the check for free nonslab page is replaced by VM_BUG_ON_PAGE,
which only check with CONFIG_DEBUG_VM enabled, but this config may
impact performance, so it only for debug.

Commit ("0937502af7c9 slub: Add check for kfree() of non slab objects.")
add the ability, which should be needed in any configs to catch the
invalid free, they even could be potential issue, eg, memory corruption,
use after free and double free, so replace VM_BUG_ON_PAGE to WARN_ON, and
add dump_page() to help use to debug the issue.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/slub.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Kefeng Wang Sept. 27, 2021, 2:08 a.m. UTC | #1
sorry´╝îwrong patch, please ignore

On 2021/9/27 10:09, Kefeng Wang wrote:
> After commit ("f227f0faf63b slub: fix unreclaimable slab stat for bulk
> free"), the check for free nonslab page is replaced by VM_BUG_ON_PAGE,
> which only check with CONFIG_DEBUG_VM enabled, but this config may
> impact performance, so it only for debug.
>
> Commit ("0937502af7c9 slub: Add check for kfree() of non slab objects.")
> add the ability, which should be needed in any configs to catch the
> invalid free, they even could be potential issue, eg, memory corruption,
> use after free and double free, so replace VM_BUG_ON_PAGE to WARN_ON, and
> add dump_page() to help use to debug the issue.
>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>   mm/slub.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index 3095b889fab4..1bfe09098485 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -3522,7 +3522,8 @@ static inline void free_nonslab_page(struct page *page, void *object)
>   {
>   	unsigned int order = compound_order(page);
>   
> -	VM_BUG_ON_PAGE(!PageCompound(page), page);
> +	if (WARN_ON(!PageCompound(page)))
> +		dump_page(page);
>   	kfree_hook(object);
>   	mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, -(PAGE_SIZE << order));
>   	__free_pages(page, order);
diff mbox series

Patch

diff --git a/mm/slub.c b/mm/slub.c
index 3095b889fab4..1bfe09098485 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3522,7 +3522,8 @@  static inline void free_nonslab_page(struct page *page, void *object)
 {
 	unsigned int order = compound_order(page);
 
-	VM_BUG_ON_PAGE(!PageCompound(page), page);
+	if (WARN_ON(!PageCompound(page)))
+		dump_page(page);
 	kfree_hook(object);
 	mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, -(PAGE_SIZE << order));
 	__free_pages(page, order);