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* [PATCH v2] mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully
@ 2013-12-13  1:09 Jianguo Wu
  2013-12-13  2:32 ` Naoya Horiguchi
  0 siblings, 1 reply; 3+ messages in thread
From: Jianguo Wu @ 2013-12-13  1:09 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Naoya Horiguchi, Andi Kleen, Mel Gorman, Wanpeng Li, Hanjun Guo,
	qiuxishi, linux-mm, linux-kernel, gong.chen

After a successful hugetlb page migration by soft offline, the source page
will either be freed into hugepage_freelists or buddy(over-commit page). If page is in
buddy, page_hstate(page) will be NULL. It will hit a NULL pointer
dereference in dequeue_hwpoisoned_huge_page().

[  890.677918] BUG: unable to handle kernel NULL pointer dereference at
 0000000000000058
[  890.685741] IP: [<ffffffff81163761>]
dequeue_hwpoisoned_huge_page+0x131/0x1d0
[  890.692861] PGD c23762067 PUD c24be2067 PMD 0
[  890.697314] Oops: 0000 [#1] SMP

So check PageHuge(page) after call migrate_pages() successfully.

Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
---
 mm/memory-failure.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index b7c1716..e5567f2 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1471,7 +1471,8 @@ static int get_any_page(struct page *page, unsigned long pfn, int flags)
 
 static int soft_offline_huge_page(struct page *page, int flags)
 {
-	int ret;
+	int ret, i;
+	unsigned long nr_pages;
 	unsigned long pfn = page_to_pfn(page);
 	struct page *hpage = compound_head(page);
 	LIST_HEAD(pagelist);
@@ -1489,6 +1490,8 @@ static int soft_offline_huge_page(struct page *page, int flags)
 	}
 	unlock_page(hpage);
 
+	nr_pages = 1 << compound_order(hpage);
+
 	/* Keep page count to indicate a given hugepage is isolated. */
 	list_move(&hpage->lru, &pagelist);
 	ret = migrate_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL,
@@ -1505,10 +1508,16 @@ static int soft_offline_huge_page(struct page *page, int flags)
 		if (ret > 0)
 			ret = -EIO;
 	} else {
-		set_page_hwpoison_huge_page(hpage);
-		dequeue_hwpoisoned_huge_page(hpage);
-		atomic_long_add(1 << compound_order(hpage),
-				&num_poisoned_pages);
+		/* overcommit hugetlb page will be freed to buddy */
+		if (PageHuge(page)) {
+			set_page_hwpoison_huge_page(hpage);
+			dequeue_hwpoisoned_huge_page(hpage);
+		} else {
+			for (i = 0; i < nr_pages; i++)
+				SetPageHWPoison(hpage + i);
+		}
+
+		atomic_long_add(nr_pages, &num_poisoned_pages);
 	}
 	return ret;
 }
-- 
1.8.2.2


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^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully
  2013-12-13  1:09 [PATCH v2] mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully Jianguo Wu
@ 2013-12-13  2:32 ` Naoya Horiguchi
  2013-12-13  3:08   ` Jianguo Wu
  0 siblings, 1 reply; 3+ messages in thread
From: Naoya Horiguchi @ 2013-12-13  2:32 UTC (permalink / raw)
  To: Jianguo Wu
  Cc: Andrew Morton, Andi Kleen, Mel Gorman, Wanpeng Li, Hanjun Guo,
	qiuxishi, linux-mm, linux-kernel, gong.chen

On Fri, Dec 13, 2013 at 09:09:52AM +0800, Jianguo Wu wrote:
> After a successful hugetlb page migration by soft offline, the source page
> will either be freed into hugepage_freelists or buddy(over-commit page). If page is in
> buddy, page_hstate(page) will be NULL. It will hit a NULL pointer
> dereference in dequeue_hwpoisoned_huge_page().
> 
> [  890.677918] BUG: unable to handle kernel NULL pointer dereference at
>  0000000000000058
> [  890.685741] IP: [<ffffffff81163761>]
> dequeue_hwpoisoned_huge_page+0x131/0x1d0
> [  890.692861] PGD c23762067 PUD c24be2067 PMD 0
> [  890.697314] Oops: 0000 [#1] SMP
> 
> So check PageHuge(page) after call migrate_pages() successfully.
> 
> Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
> ---
>  mm/memory-failure.c | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index b7c1716..e5567f2 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1471,7 +1471,8 @@ static int get_any_page(struct page *page, unsigned long pfn, int flags)
>  
>  static int soft_offline_huge_page(struct page *page, int flags)
>  {
> -	int ret;
> +	int ret, i;
> +	unsigned long nr_pages;
>  	unsigned long pfn = page_to_pfn(page);
>  	struct page *hpage = compound_head(page);
>  	LIST_HEAD(pagelist);
> @@ -1489,6 +1490,8 @@ static int soft_offline_huge_page(struct page *page, int flags)
>  	}
>  	unlock_page(hpage);
>  
> +	nr_pages = 1 << compound_order(hpage);
> +
>  	/* Keep page count to indicate a given hugepage is isolated. */
>  	list_move(&hpage->lru, &pagelist);
>  	ret = migrate_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL,
> @@ -1505,10 +1508,16 @@ static int soft_offline_huge_page(struct page *page, int flags)
>  		if (ret > 0)
>  			ret = -EIO;
>  	} else {
> -		set_page_hwpoison_huge_page(hpage);
> -		dequeue_hwpoisoned_huge_page(hpage);
> -		atomic_long_add(1 << compound_order(hpage),
> -				&num_poisoned_pages);
> +		/* overcommit hugetlb page will be freed to buddy */
> +		if (PageHuge(page)) {
> +			set_page_hwpoison_huge_page(hpage);
> +			dequeue_hwpoisoned_huge_page(hpage);
> +		} else {
> +			for (i = 0; i < nr_pages; i++)
> +				SetPageHWPoison(hpage + i);

Why don't you set PageHWPoison only on the error raw page instead
of the whole error hugepage, or is there some problem of doing so?

Thanks,
Naoya

> +		}
> +
> +		atomic_long_add(nr_pages, &num_poisoned_pages);
>  	}
>  	return ret;
>  }
> -- 
> 1.8.2.2
> 
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
> 

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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully
  2013-12-13  2:32 ` Naoya Horiguchi
@ 2013-12-13  3:08   ` Jianguo Wu
  0 siblings, 0 replies; 3+ messages in thread
From: Jianguo Wu @ 2013-12-13  3:08 UTC (permalink / raw)
  To: Naoya Horiguchi
  Cc: Andrew Morton, Andi Kleen, Mel Gorman, Wanpeng Li, Hanjun Guo,
	qiuxishi, linux-mm, linux-kernel, gong.chen

Hi,

On 2013/12/13 10:32, Naoya Horiguchi wrote:

> On Fri, Dec 13, 2013 at 09:09:52AM +0800, Jianguo Wu wrote:
>> After a successful hugetlb page migration by soft offline, the source page
>> will either be freed into hugepage_freelists or buddy(over-commit page). If page is in
>> buddy, page_hstate(page) will be NULL. It will hit a NULL pointer
>> dereference in dequeue_hwpoisoned_huge_page().
>>
>> [  890.677918] BUG: unable to handle kernel NULL pointer dereference at
>>  0000000000000058
>> [  890.685741] IP: [<ffffffff81163761>]
>> dequeue_hwpoisoned_huge_page+0x131/0x1d0
>> [  890.692861] PGD c23762067 PUD c24be2067 PMD 0
>> [  890.697314] Oops: 0000 [#1] SMP
>>
>> So check PageHuge(page) after call migrate_pages() successfully.
>>
>> Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
>> ---
>>  mm/memory-failure.c | 19 ++++++++++++++-----
>>  1 file changed, 14 insertions(+), 5 deletions(-)
>>
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index b7c1716..e5567f2 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -1471,7 +1471,8 @@ static int get_any_page(struct page *page, unsigned long pfn, int flags)
>>  
>>  static int soft_offline_huge_page(struct page *page, int flags)
>>  {
>> -	int ret;
>> +	int ret, i;
>> +	unsigned long nr_pages;
>>  	unsigned long pfn = page_to_pfn(page);
>>  	struct page *hpage = compound_head(page);
>>  	LIST_HEAD(pagelist);
>> @@ -1489,6 +1490,8 @@ static int soft_offline_huge_page(struct page *page, int flags)
>>  	}
>>  	unlock_page(hpage);
>>  
>> +	nr_pages = 1 << compound_order(hpage);
>> +
>>  	/* Keep page count to indicate a given hugepage is isolated. */
>>  	list_move(&hpage->lru, &pagelist);
>>  	ret = migrate_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL,
>> @@ -1505,10 +1508,16 @@ static int soft_offline_huge_page(struct page *page, int flags)
>>  		if (ret > 0)
>>  			ret = -EIO;
>>  	} else {
>> -		set_page_hwpoison_huge_page(hpage);
>> -		dequeue_hwpoisoned_huge_page(hpage);
>> -		atomic_long_add(1 << compound_order(hpage),
>> -				&num_poisoned_pages);
>> +		/* overcommit hugetlb page will be freed to buddy */
>> +		if (PageHuge(page)) {
>> +			set_page_hwpoison_huge_page(hpage);
>> +			dequeue_hwpoisoned_huge_page(hpage);
>> +		} else {
>> +			for (i = 0; i < nr_pages; i++)
>> +				SetPageHWPoison(hpage + i);
> 
> Why don't you set PageHWPoison only on the error raw page instead
> of the whole error hugepage, or is there some problem of doing so?
> 

Oh, yes, we should only poison the error raw page. I will resend a new version.

Thanks,
Jianguo Wu

> Thanks,
> Naoya
> 
>> +		}
>> +
>> +		atomic_long_add(nr_pages, &num_poisoned_pages);
>>  	}
>>  	return ret;
>>  }
>> -- 
>> 1.8.2.2
>>
>>
>> --
>> To unsubscribe, send a message with 'unsubscribe linux-mm' in
>> the body to majordomo@kvack.org.  For more info on Linux MM,
>> see: http://www.linux-mm.org/ .
>> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
>>
> 
> .
> 



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^ permalink raw reply	[flat|nested] 3+ messages in thread

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2013-12-13  1:09 [PATCH v2] mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully Jianguo Wu
2013-12-13  2:32 ` Naoya Horiguchi
2013-12-13  3:08   ` Jianguo Wu

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