Subject: Re: [PATCH 3/4] drivers/net/can/mscan/mpc5xxx_can.c: Add of_node_put to avoid memory leak

From: Wolfgang Grandegger <[email-masked]>
Date: Tue, 31 Aug 2010 21:22:07 +0200

On 08/31/2010 09:10 PM, Wolfram Sang wrote:
> On Tue, Aug 31, 2010 at 07:44:00PM +0200, Julia Lawall wrote:
>> Add a call to of_node_put in the error handling code following a call to
>> of_find_matching_node.
>>
>> This patch also moves the existing call to of_node_put after the call to
>> iounmap in the error handling code, to make it possible to jump to
>> of_node_put without doing iounmap.  These appear to be disjoint operations,
>> so the ordering doesn't matter.
>>
>> This patch furthermore changes the -ENODEV result in the error handling
>> code for of_find_matching_node to a return of 0, as found in the error
>> handling code for of_iomap, because the return type of the function is
>> unsigned.
>>
>> The semantic match that finds this problem is as follows:
>> (http://coccinelle.lip6.fr/)
>>
>> // <smpl>
>> @r exists@
>> local idexpression x;
>> expression E,E1,E2;
>> statement S;
>> @@
>>
>> *x = 
>> (of_find_node_by_path
>> |of_find_node_by_name
>> |of_find_node_by_phandle
>> |of_get_parent
>> |of_get_next_parent
>> |of_get_next_child
>> |of_find_compatible_node
>> |of_match_node
>> |of_find_node_by_type
>> |of_find_node_with_property
>> |of_find_matching_node
>> |of_parse_phandle
>> )(...);
>> ...
>> if (x == NULL) S
>> <... when != x = E
>> *if (...) {
>>   ... when != of_node_put(x)
>>       when != if (...) { ... of_node_put(x); ... }
>> (
>>   return <+...x...+>;
>> |
>> *  return ...;
>> )
>> }
>> ...>
>> (
>> E2 = x;
>> |
>> of_node_put(x);
>> )
>> // </smpl>
>>
>> Signed-off-by: Julia Lawall <[email-masked]>
> 
> Reviewed-by: Wolfram Sang <[email-masked]>

Acked-by: Wolfgang Grandegger <[email-masked]>