net/rfkill/core.c: Avoid leaving freed data in a list

The list_for_each_entry loop can fail, in which case the list element is
not removed from the list rfkill_fds.  Since this list is not accessed by
the loop, the addition of &data->list into the list is just moved after the
loop.

The sematic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression E,E1,E2;
identifier l;
@@

*list_add(&E->l,E1);
... when != E1
    when != list_del(&E->l)
    when != list_del_init(&E->l)
    when != E = E2
*kfree(E);// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index 0198191..be90640 100644 (file)
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c
@@ -1024,7 +1024,6 @@ static int rfkill_fop_open(struct inode *inode, struct file *file)
         * start getting events from elsewhere but hold mtx to get
         * startup events added first
         */
-       list_add(&data->list, &rfkill_fds);
 
        list_for_each_entry(rfkill, &rfkill_list, node) {
                ev = kzalloc(sizeof(*ev), GFP_KERNEL);
@@ -1033,6 +1032,7 @@ static int rfkill_fop_open(struct inode *inode, struct file *file)
                rfkill_fill_event(&ev->ev, rfkill, RFKILL_OP_ADD);
                list_add_tail(&ev->list, &data->events);
        }
+       list_add(&data->list, &rfkill_fds);
        mutex_unlock(&data->mtx);
        mutex_unlock(&rfkill_global_mutex);