#1621: Kernel oopses in ath_draintxq, and other cases where
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Reporter: anonymous | Owner: mtaylor
Type: defect | Status: assigned
Priority: blocker | Milestone:
Component: madwifi: driver | Version: trunk
Resolution: | Keywords: oops crash
Patch_attached: 0 |
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Comment (by mtaylor):
r2792 is "Temporary workaround to refcount bugs exposed by r2792"
The patch basically puts a big nasty message about this being a quick and
dirty hack, and then bumps the reference count on the node.
If the node is reclaimed more than once, kfree is called on the same
address. Behavior is allocator specific. All the SKB may still also
point to the node, resulting in use of the node after free.
--- net80211/ieee80211_node.c (revision 2827)
+++ net80211/ieee80211_node.c (working copy)
@@ -738,6 +738,21 @@
ni->ni_table = nt;
tni = ieee80211_ref_node(ni);
+ /* MT: BEGIN HACK
+ * XXX: r2792 fixed a bug where ieee80211_ref_node was being
+ * invoked five times on ni because it was passed to
TAILQ_INSERT_TAIL
+ * which happens to evaluate it's value five times. This fixed a
problem
+ * where we were gaining four extra references, but unfortunately
exposed
+ * other bugs which cause kernel panics. I am working on a fix
for this as part
+ * of ticket #1621. In the meantime, adding these references
back is 'wrong'
+ * but better than getting five new critical defects per day
while debugging.
+ */
+ ieee80211_ref_node(ni);ieee80211_ref_node(ni);
+ ieee80211_ref_node(ni);ieee80211_ref_node(ni);
+ /*
+ * END HACK
+ */
+
--
Ticket URL: <http://madwifi.org/ticket/1621#comment:11>
madwifi.org <http://madwifi.org/>
Multiband Atheros Driver for Wireless Fidelity
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