On Sun, Jun 07, 2015 at 08:36:45AM +0200, Julia Lawall wrote:
>
>
>On Sun, 7 Jun 2015, Firo Yang wrote:
>
>> On Sat, Jun 06, 2015 at 05:05:04AM -0700, Eric Dumazet wrote:
>> >On Sat, 2015-06-06 at 19:35 +0800, Firo Yang wrote:
>> >> A smatch warning.
>> >> When kmem_cache_alloc() failed to alloc memory, a null pointer
>> >> will be returned. Redeference null pointer will generate
>> >
>> >
>> >Dereferencing a null pointer will crash.
>> >
>> >> an unnecessary oops. So, use it after check.
>> >>
>> >> Signed-off-by: Firo Yang <firogm@xxxxxxxxx>
>> >> ---
>> >> net/ipv4/fib_trie.c | 3 ++-
>> >> 1 file changed, 2 insertions(+), 1 deletion(-)
>> >>
>> >> diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
>> >> index 01bce15..34094c7 100644
>> >> --- a/net/ipv4/fib_trie.c
>> >> +++ b/net/ipv4/fib_trie.c
>> >> @@ -326,12 +326,13 @@ static inline void empty_child_dec(struct key_vector *n)
>> >> static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
>> >> {
>> >> struct tnode *kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
>> >> - struct key_vector *l = kv->kv;
>> >> + struct key_vector *l;
>> >>
>> >> if (!kv)
>> >> return NULL;
>> >>
>> >> /* initialize key vector */
>> >> + l = kv->kv;
>> >> l->key = key;
>> >> l->pos = 0;
>> >> l->bits = 0;
>> >
>> >Fixes: dc35dbeda3e0 ("fib_trie: Add tnode struct as a container for fields not needed in key_vector")
>> >Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
>> >
>> >Thanks.
>>
>> Hi Eric,
>> Please discard this useless patch figured out by Alexander Duyck.
>> I will send a patch to Smatch for eliminating the negative warning.
>
>I think that many people would make the same mistake when looking at the
>code. The change doesn't seem to hurt anything?
Actually, yes. But it does imporve nothing but coding style.
I think Alexander's code style make function more compact is also a
good code style. So, just keep it original.
Firo
>
>julia
--
--
To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
