Re: [PATCH] fs/hugetlbfs/inode.c: Ensure generic_hugetlb_get_unmapped_area() returns higher address than mmap_min_addr

[Kirill A . Shutemov]

On Fri, Jul 05, 2024 at 02:11:50AM -0500, Donet Tom wrote:
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index 412f295acebe..428fd2f0e4c4 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -228,7 +228,7 @@ generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
>  
>  	if (len & ~huge_page_mask(h))
>  		return -EINVAL;
> -	if (len > TASK_SIZE)
> +	if (len > mmap_end - mmap_min_addr)
>  		return -ENOMEM;
>  
>  	if (flags & MAP_FIXED) {
> @@ -240,7 +240,7 @@ generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
>  	if (addr) {
>  		addr = ALIGN(addr, huge_page_size(h));
>  		vma = find_vma(mm, addr);
> -		if (mmap_end - len >= addr &&
> +		if (mmap_end - len >= addr && addr >= mmap_min_addr &&
>  		    (!vma || addr + len <= vm_start_gap(vma)))
>  			return addr;
>  	}

There's more difference with generic_get_unmapped_area() than what you are
fixing. I think we also need vm_end_gap() here.

Hugetlb code duplication is annoying.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov