[PATCH] [158/275] x25: Do not reference freed memory.

From: Andi Kleen
Date: Wed Mar 30 2011 - 17:37:45 EST


2.6.35-longterm review patch. If anyone has any objections, please let me know.

------------------
From: David S. Miller <davem@xxxxxxxxxxxxx>

commit 96642d42f076101ba98866363d908cab706d156c upstream.

In x25_link_free(), we destroy 'nb' before dereferencing
'nb->dev'. Don't do this, because 'nb' might be freed
by then.

Reported-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Tested-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
net/x25/x25_link.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

Index: linux-2.6.35.y/net/x25/x25_link.c
===================================================================
--- linux-2.6.35.y.orig/net/x25/x25_link.c 2011-03-29 22:51:02.348663073 -0700
+++ linux-2.6.35.y/net/x25/x25_link.c 2011-03-29 23:03:01.541260733 -0700
@@ -392,9 +392,12 @@
write_lock_bh(&x25_neigh_list_lock);

list_for_each_safe(entry, tmp, &x25_neigh_list) {
+ struct net_device *dev;
+
nb = list_entry(entry, struct x25_neigh, node);
+ dev = nb->dev;
__x25_remove_neigh(nb);
- dev_put(nb->dev);
+ dev_put(dev);
}
write_unlock_bh(&x25_neigh_list_lock);
}
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