From: Julia Lawall <julia@diku.dk>
The function x25_get_neigh increments a reference count. At the point of
the second goto out, the result of calling x25_get_neigh is only stored in
a local variable, and thus no one outside the function will be able to
decrease the reference count. Thus, x25_neigh_put should be called before
the return in this case.
The problem was found using the following semantic match.
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@@
type T,T1,T2;
identifier E;
statement S;
expression x1,x2,x3;
int ret;
@@
T E;
...
* if ((E = x25_get_neigh(...)) == NULL)
S
... when != x25_neigh_put(...,(T1)E,...)
when != if (E != NULL) { ... x25_neigh_put(...,(T1)E,...); ...}
when != x1 = (T1)E
when != E = x3;
when any
if (...) {
... when != x25_neigh_put(...,(T2)E,...)
when != if (E != NULL) { ... x25_neigh_put(...,(T2)E,...); ...}
when != x2 = (T2)E
(
* return;
|
* return ret;
)
}
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
---
diff -u -p a/net/x25/x25_forward.c b/net/x25/x25_forward.c
--- a/net/x25/x25_forward.c 2008-01-01 09:49:39.000000000 +0100
+++ b/net/x25/x25_forward.c 2008-01-01 14:26:05.000000000 +0100
@@ -118,13 +118,14 @@ int x25_forward_data(int lci, struct x25
goto out;
if ( (skbn = pskb_copy(skb, GFP_ATOMIC)) == NULL){
- goto out;
+ goto output;
}
x25_transmit_link(skbn, nb);
- x25_neigh_put(nb);
rc = 1;
+output:
+ x25_neigh_put(nb);
out:
return rc;
}
--
