Re: [Patch] mm/sparse.c: Check the return value ofsparse_index_alloc().

From: Dave Hansen
Date: Mon Nov 19 2007 - 16:17:18 EST


On Thu, 2007-11-15 at 21:54 +0800, WANG Cong wrote:
> Since sparse_index_alloc() can return NULL on memory allocation failure,
> we must deal with the failure condition when calling it.
>
> Signed-off-by: WANG Cong <xiyou.wangcong@xxxxxxxxx>
> Cc: Christoph Lameter <clameter@xxxxxxx>
> Cc: Rik van Riel <riel@xxxxxxxxxx>
>
> ---
>
> diff --git a/Makefile b/Makefile
> diff --git a/mm/sparse.c b/mm/sparse.c
> index e06f514..d245e59 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -83,6 +83,8 @@ static int __meminit sparse_index_init(unsigned long section_nr, int nid)
> return -EEXIST;
>
> section = sparse_index_alloc(nid);
> + if (!section)
> + return -ENOMEM;
> /*
> * This lock keeps two different sections from
> * reallocating for the same index

Oddly enough, sparse_add_one_section() doesn't seem to like to check
its allocations. The usemap is checked, but not freed on error. If you
want to fix this up, I think it needs a little more love than just two
lines.

Do you want to try to add some actual error handling to
sparse_add_one_section()?

-- Dave

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