On 2023/6/28 3:30, Andrew Morton wrote:
> On Tue, 27 Jun 2023 19:28:08 +0800 Miaohe Lin <linmiaohe@xxxxxxxxxx> wrote:
>
>> When page_handle_poison() fails to handle the hugepage or free page in
>> retry path, soft_offline_page() will return 0 while -EBUSY is expected
>> in this case.
>
> What are the user visible effects of the bug?
The user will think soft_offline_page succeeds while it failed in fact. So user
will not try again later in this case.
>
>> Fixes: b94e02822deb ("mm,hwpoison: try to narrow window race for free pages")
>>
>> ...
>>
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -2737,10 +2737,13 @@ int soft_offline_page(unsigned long pfn, int flags)
>> if (ret > 0) {
>> ret = soft_offline_in_use_page(page);
>> } else if (ret == 0) {
>> - if (!page_handle_poison(page, true, false) && try_again) {
>> - try_again = false;
>> - flags &= ~MF_COUNT_INCREASED;
>> - goto retry;
>> + if (!page_handle_poison(page, true, false)) {
>> + if (try_again) {
>> + try_again = false;
>> + flags &= ~MF_COUNT_INCREASED;
>> + goto retry;
>> + }
>> + ret = -EBUSY;
>> }
>> }
> .
>
