Adam Litke wrote:
> On Tue, 2008-03-04 at 11:51 -0800, Andrew Morton wrote:
>> hugetlb-correct-page-count-for-surplus-huge-pages.patch adds:
>>
>> if (page) {
>> /*
>> * This page is now managed by the hugetlb allocator and has
>> * no users -- drop the buddy allocator's reference.
>> */
>> int page_count = put_page_testzero(page);
>> BUG_ON(page_count != 0);
>>
>>
>
> Ugh I got bitten by put_page_testzero(). When it returns 1, the page
> count is zero (not the page count).
>
> My initial version had a BUG_ON() with side-effects. When a reviewer
> pointed it out, I thought I could fix the patch up on its way out the
> door. I have self-administered my punishment. This patch will fix it:
Hi Adam,
Thanks the patch fixes the kernel bug while running the libhugetlbfs test.
Tested-by: Kamalesh Babulal <[EMAIL PROTECTED]>
>
> Signed-off-by: Adam Litke <[EMAIL PROTECTED]>
>
> --- mm/hugetlb.c.orig 2008-03-04 13:36:30.000000000 -0800
> +++ mm/hugetlb.c 2008-03-04 13:39:30.000000000 -0800
> @@ -291,8 +291,8 @@ static struct page *alloc_buddy_huge_pag
> * This page is now managed by the hugetlb allocator and has
> * no users -- drop the buddy allocator's reference.
> */
> - int page_count = put_page_testzero(page);
> - BUG_ON(page_count != 0);
> + put_page_testzero(page);
> + VM_BUG_ON(page_count(page));
> nid = page_to_nid(page);
> set_compound_page_dtor(page, free_huge_page);
> /*
>
--
Thanks & Regards,
Kamalesh Babulal,
Linux Technology Center,
IBM, ISTL.
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