IPoIB: In unicast_arp_send(), only free newly-created paths

If path_rec_start() returns error, call path_free() only if the path
was newly-created.  If we free an existing path whose valid flag was zero,
(but do not detach it from the list) we cause corruption of the
path list (of which it is a member), and get a kernel crash.

The simplest solution is to not free an existing path -- just leave it
in the list as-is (i.e., with its valid flag cleared).

Thanks to Yossi Etigin of Voltaire for identifying the problem flow
which caused the kernel crash.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Moni Shua <monis@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Jack Morgenstein 2009-02-17 14:51:47 -08:00 committed by Roland Dreier
parent f3b8436ad9
commit 71d98b4628

View File

@ -660,8 +660,12 @@ static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
path = __path_find(dev, phdr->hwaddr + 4);
if (!path || !path->valid) {
if (!path)
int new_path = 0;
if (!path) {
path = path_rec_create(dev, phdr->hwaddr + 4);
new_path = 1;
}
if (path) {
/* put pseudoheader back on for next time */
skb_push(skb, sizeof *phdr);
@ -669,7 +673,8 @@ static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
if (!path->query && path_rec_start(dev, path)) {
spin_unlock_irqrestore(&priv->lock, flags);
path_free(dev, path);
if (new_path)
path_free(dev, path);
return;
} else
__path_add(dev, path);