Re: [PATCH v3 2/3] fix hugetlb memory check in vma_dump_size()

[Michal Hocko <mhocko@suse.cz>]

On Wed 03-04-13 14:35:37, Naoya Horiguchi wrote:
> Documentation/filesystems/proc.txt says about coredump_filter bitmask,
> 
>   Note bit 0-4 doesn't effect any hugetlb memory. hugetlb memory are only
>   effected by bit 5-6.
> 
> However current code can go into the subsequent flag checks of bit 0-4
> for vma(VM_HUGETLB). So this patch inserts 'return' and makes it work
> as written in the document.
> 
> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Cc: stable@vger.kernel.org

Just for the record. It should be stable for 3.7+ since (314e51b98)
becuase then have lost VM_RESERVED check which used to stop hugetlb
mappings.

Acked-by: Michal Hocko <mhocko@suse.cz>

> ---
>  fs/binfmt_elf.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git v3.9-rc3.orig/fs/binfmt_elf.c v3.9-rc3/fs/binfmt_elf.c
> index 3939829..86af964 100644
> --- v3.9-rc3.orig/fs/binfmt_elf.c
> +++ v3.9-rc3/fs/binfmt_elf.c
> @@ -1137,6 +1137,7 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma,
>  			goto whole;
>  		if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
>  			goto whole;
> +		return 0;
>  	}
>  
>  	/* Do not dump I/O mapped devices or special mappings */
> -- 
> 1.7.11.7
> 

-- 
Michal Hocko
SUSE Labs

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