Re: [patch] fix hugetlbfs quota leak

Andrew Morton
2008-01-11T09:44:09Z

On Thu, 10 Jan 2008 22:24:12 -0800 "Ken Chen" <kenchen@google.com> wrote:

> In the error path of both shared and private hugetlb page allocation,
> the file system quota is never undone, leading to fs quota leak.
> Patch to fix them up.
>

Thanks.

>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 7224a4f..b2863f3 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -420,6 +420,8 @@ static struct page *alloc_huge_page_private(struct
> vm_area_struct *vma,

Your client is wordwrapping patches.

> spin_unlock(&hugetlb_lock);
> if (!page)
> page = alloc_buddy_huge_page(vma, addr);
> + if (!page)
> + hugetlb_put_quota(vma->vm_file->f_mapping, 1);
> return page ? page : ERR_PTR(-VM_FAULT_OOM);
> }

The code was already fairly ugly and inefficient. Let's improve that
rather than worsening it?

> @@ -1206,8 +1208,10 @@ int hugetlb_reserve_pages(struct inode *inode,
> long from, long to)
> if (hugetlb_get_quota(inode->i_mapping, chg))
> return -ENOSPC;
> ret = hugetlb_acct_memory(chg);
> - if (ret < 0)
> + if (ret < 0) {
> + hugetlb_put_quota(inode->i_mapping, chg);
> return ret;
> + }
> region_add(&inode->i_mapping->private_list, from, to);
> return 0;
> }

--- a/mm/hugetlb.c~hugetlbfs-fix-quota-leak
+++ a/mm/hugetlb.c
@@ -418,9 +418,14 @@ static struct page *alloc_huge_page_priv
if (free_huge_pages > resv_huge_pages)
page = dequeue_huge_page(vma, addr);
spin_unlock(&hugetlb_lock);
- if (!page)
+ if (!page) {
page = alloc_buddy_huge_page(vma, addr);
- return page ? page : ERR_PTR(-VM_FAULT_OOM);
+ if (!page) {
+ hugetlb_put_quota(vma->vm_file->f_mapping, 1);
+ return ERR_PTR(-VM_FAULT_OOM);
+ }
+ }
+ return page;
}

static struct page *alloc_huge_page(struct vm_area_struct *vma,
@@ -1206,8 +1211,10 @@ int hugetlb_reserve_pages(struct inode *
if (hugetlb_get_quota(inode->i_mapping, chg))
return -ENOSPC;
ret = hugetlb_acct_memory(chg);
- if (ret < 0)
+ if (ret < 0) {
+ hugetlb_put_quota(inode->i_mapping, chg);
return ret;
+ }
region_add(&inode->i_mapping->private_list, from, to);
return 0;
}
_