[PATCH v2] mm: hugetlb: fix type of delta parameter and related local variables in gather_surplus_pages()

[PATCH v2] mm: hugetlb: fix type of delta parameter and related local variables in gather_surplus_pages()

[Liu Xiang]

On 64-bit machine, delta variable in hugetlb_acct_memory() may be larger
than 0xffffffff, but gather_surplus_pages() can only use the low 32-bit
value now. So we need to fix type of delta parameter and related local
variables in gather_surplus_pages().

Reported-by: Ma Chenggong <ma.chenggong@zlingsmart.com>
Signed-off-by: Liu Xiang <liu.xiang@zlingsmart.com>
Signed-off-by: Pan Jiagen <pan.jiagen@zlingsmart.com>

---
Changes in v2:
  as suggested by Mike, apply the same fix to the related local
  variables in gather_surplus_pages().
---
---
 mm/hugetlb.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 37f15c3..3797401 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1943,13 +1943,14 @@ struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
  * Increase the hugetlb pool such that it can accommodate a reservation
  * of size 'delta'.
  */
-static int gather_surplus_pages(struct hstate *h, int delta)
+static int gather_surplus_pages(struct hstate *h, long delta)
 	__must_hold(&hugetlb_lock)
 {
 	struct list_head surplus_list;
 	struct page *page, *tmp;
-	int ret, i;
-	int needed, allocated;
+	int ret;
+	long i;
+	long needed, allocated;
 	bool alloc_ok = true;
 
 	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
-- 
1.9.1

Re: [PATCH v2] mm: hugetlb: fix type of delta parameter and related local variables in gather_surplus_pages()

[Mike Kravetz]

On 11/19/20 5:48 AM, Liu Xiang wrote:
> On 64-bit machine, delta variable in hugetlb_acct_memory() may be larger
> than 0xffffffff, but gather_surplus_pages() can only use the low 32-bit
> value now. So we need to fix type of delta parameter and related local
> variables in gather_surplus_pages().
> 
> Reported-by: Ma Chenggong <ma.chenggong@zlingsmart.com>
> Signed-off-by: Liu Xiang <liu.xiang@zlingsmart.com>
> Signed-off-by: Pan Jiagen <pan.jiagen@zlingsmart.com>
> 
> ---
> Changes in v2:
>   as suggested by Mike, apply the same fix to the related local
>   variables in gather_surplus_pages().
> ---
> ---
>  mm/hugetlb.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)

Thank you,

Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>

-- 
Mike Kravetz