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

[WANG Cong <xiyou.wangcong@gmail.com>]

On Mon, Nov 19, 2007 at 01:17:02PM -0800, Dave Hansen wrote:
>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@gmail.com>
>> Cc: Christoph Lameter <clameter@sgi.com>
>> Cc: Rik van Riel <riel@redhat.com>
>> 
>> ---
>> 
>> 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.  

Er, right. I missed this point.

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

Yes, I will have a try. And memory_present() also doesn't check it.
More patches around this will come up soon. Since Andrew has included
the above patch, so I won't remake it with others together.

Andrew, is this OK for you?

Thanks.