Re: [PATCH] rmap: fix anon_vma_fork() memory leak

[Linus Torvalds]

On Sun, 4 Apr 2010, Rik van Riel wrote:
>
> Fix a memory leak in anon_vma_fork(), where we fail to tear down the
> anon_vmas attached to the new VMA in case setting up the new anon_vma
> fails.
> 
> Reported-by: Minchan Kim <minchan.kim@xxxxxxxxx>
> Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>
> Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx>
> ---
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index fcd593c..fb7ce99 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -231,6 +231,7 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
>  
>   out_error_free_anon_vma:
>  	anon_vma_free(anon_vma);
> +	unlink_anon_vmas(vma);
>   out_error:
>  	return -ENOMEM;
>  }

This looks _very_ wrong to me.

Shouldn't the unlink_anon_vmas() be in the "out_error" case? IOW, we 
should do it even if the "anon_vma_alloc()" failed, nbot just if the 
"anon_vma_chain_alloc()" failed?

No?

What am I missing?

			Linus
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