2015-08-06 08:11:13

by Wanpeng Li

[permalink] [raw]
Subject: [PATCH] mm/hwpoison: fix page refcount of unkown non LRU page

After try to drain pages from pagevec/pageset, we try to get reference
count of the page again, however, the reference count of the page is
not reduced if the page is still not on LRU list. This patch fix it by
adding the put_page() to drop the page reference which is from
__get_any_page().

Signed-off-by: Wanpeng Li <[email protected]>
---
mm/memory-failure.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index c53543d..23163d0 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1535,6 +1535,8 @@ static int get_any_page(struct page *page, unsigned long pfn, int flags)
*/
ret = __get_any_page(page, pfn, 0);
if (!PageLRU(page)) {
+ /* Drop page reference which is from __get_any_page() */
+ put_page(page);
pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n",
pfn, page->flags);
return -EIO;
--
1.7.1


2015-08-07 07:50:20

by Naoya Horiguchi

[permalink] [raw]
Subject: Re: [PATCH] mm/hwpoison: fix page refcount of unkown non LRU page

On Thu, Aug 06, 2015 at 04:09:37PM +0800, Wanpeng Li wrote:
> After try to drain pages from pagevec/pageset, we try to get reference
> count of the page again, however, the reference count of the page is
> not reduced if the page is still not on LRU list. This patch fix it by
> adding the put_page() to drop the page reference which is from
> __get_any_page().
>
> Signed-off-by: Wanpeng Li <[email protected]>

This fix is correct. Thanks you for catching this, Wanpeng!

Acked-by: Naoya Horiguchi <[email protected]>

BTW, I think this patch is worth sending to stable tree. It seems that
the latest change around this code is given by the following commit:

commit af8fae7c08862bb85c5cf445bf9b36314b82111f
Author: Naoya Horiguchi <[email protected]>
Date: Fri Feb 22 16:34:03 2013 -0800

mm/memory-failure.c: clean up soft_offline_page()

. I think that this bug existed before this commit, but this patch is
cleanly applicable only after this patch, so I think tagging
"Cc: [email protected] # 3.9+" is good.

Thanks,
Naoya Horiguchi

> ---
> mm/memory-failure.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index c53543d..23163d0 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1535,6 +1535,8 @@ static int get_any_page(struct page *page, unsigned long pfn, int flags)
> */
> ret = __get_any_page(page, pfn, 0);
> if (!PageLRU(page)) {
> + /* Drop page reference which is from __get_any_page() */
> + put_page(page);
> pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n",
> pfn, page->flags);
> return -EIO;
> --
> 1.7.1
> -

2015-08-07 09:28:16

by Wanpeng Li

[permalink] [raw]
Subject: Re: [PATCH] mm/hwpoison: fix page refcount of unkown non LRU page



On 8/7/15 3:46 PM, Naoya Horiguchi wrote:
> On Thu, Aug 06, 2015 at 04:09:37PM +0800, Wanpeng Li wrote:
>> After try to drain pages from pagevec/pageset, we try to get reference
>> count of the page again, however, the reference count of the page is
>> not reduced if the page is still not on LRU list. This patch fix it by
>> adding the put_page() to drop the page reference which is from
>> __get_any_page().
>>
>> Signed-off-by: Wanpeng Li <[email protected]>
> This fix is correct. Thanks you for catching this, Wanpeng!
>
> Acked-by: Naoya Horiguchi <[email protected]>

Thanks, :)

>
> BTW, I think this patch is worth sending to stable tree. It seems that
> the latest change around this code is given by the following commit:
>
> commit af8fae7c08862bb85c5cf445bf9b36314b82111f
> Author: Naoya Horiguchi <[email protected]>
> Date: Fri Feb 22 16:34:03 2013 -0800
>
> mm/memory-failure.c: clean up soft_offline_page()
>
> . I think that this bug existed before this commit, but this patch is
> cleanly applicable only after this patch, so I think tagging
> "Cc: [email protected] # 3.9+" is good.

I will add this in v2.

Regards,
Wanpeng Li

>
> Thanks,
> Naoya Horiguchi
>
>> ---
>> mm/memory-failure.c | 2 ++
>> 1 files changed, 2 insertions(+), 0 deletions(-)
>>
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index c53543d..23163d0 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -1535,6 +1535,8 @@ static int get_any_page(struct page *page, unsigned long pfn, int flags)
>> */
>> ret = __get_any_page(page, pfn, 0);
>> if (!PageLRU(page)) {
>> + /* Drop page reference which is from __get_any_page() */
>> + put_page(page);
>> pr_info("soft_offline: %#lx: unknown non LRU page type %lx\n",
>> pfn, page->flags);
>> return -EIO;
>> --
>> 1.7.1