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 <wanpeng.li@xxxxxxxxxxx>
> This fix is correct. Thanks you for catching this, Wanpeng!
>
> Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
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 <n-horiguchi@xxxxxxxxxxxxx>
> 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: stable@xxxxxxxxxxxxxxx # 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
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