diff mbox

[1/5] fs/hugetlbfs/inode.c: Fix pgoff alignment checking on 32-bit

Message ID 13092909493748-git-send-email-beckyb@kernel.crashing.org (mailing list archive)
State Accepted, archived
Headers show

Commit Message

Becky Bruce June 28, 2011, 7:54 p.m. UTC 
From: Becky Bruce <beckyb@kernel.crashing.org>

This:

vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT)

is incorrect on 32-bit.  It causes us to & the pgoff with
something that looks like this (for a 4m hugepage): 0xfff003ff.
The mask should be flipped and *then* shifted, to give you
0x0000_03fff.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
---
 fs/hugetlbfs/inode.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

Comments

Benjamin Herrenschmidt July 19, 2011, 4:43 a.m. UTC | #1 
Andrew, Anybody ? Can I have an -mm ack for this ?

Cheers,
Ben.

On Tue, 2011-06-28 at 14:54 -0500, Becky Bruce wrote:
> From: Becky Bruce <beckyb@kernel.crashing.org>
> 
> This:
> 
> vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT)
> 
> is incorrect on 32-bit.  It causes us to & the pgoff with
> something that looks like this (for a 4m hugepage): 0xfff003ff.
> The mask should be flipped and *then* shifted, to give you
> 0x0000_03fff.
> 
> Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
> ---
>  fs/hugetlbfs/inode.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index 7aafeb8..537a209 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -94,7 +94,7 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
>  	vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
>  	vma->vm_ops = &hugetlb_vm_ops;
>  
> -	if (vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT))
> +	if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
>  		return -EINVAL;
>  
>  	vma_len = (loff_t)(vma->vm_end - vma->vm_start);
diff mbox

Patch

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 7aafeb8..537a209 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -94,7 +94,7 @@  static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 	vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
 	vma->vm_ops = &hugetlb_vm_ops;
 
-	if (vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT))
+	if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 		return -EINVAL;
 
 	vma_len = (loff_t)(vma->vm_end - vma->vm_start);