On Tue, 2008-11-11 at 11:52 +0800, Zhu Yi wrote:
> > > [<ffffffff80257315>] synchronize_rcu+0x35/0x40
> >
> > > [<ffffffff80551d17>] sta_info_destroy+0x47/0x110
> > > [<ffffffff80559156>] ieee80211_set_disassoc+0x146/0x250
> > > [<ffffffff805593d5>] ieee80211_sta_req_auth+0x85/0x90
> > > [<ffffffff8055b156>] ieee80211_notify_mac+0x56/0xa0
> > We can fix this by using RTNL locking instead, not sure though that'll
> > work because I don't know how iwl3945 calls this, I'll let Tomas deal
> > with it.
>
> Johannes, this scheduleing in atomic has nothing to do with the caller.
> iwl3945 already calls it in a workqueue. The problem is inside
> ieee80211_notify_mac(). Unfortunately, iwl3945/iwlagn turns to be the
> only user at this time.
I see. But the suggestion above is valid nonetheless and works fine if
it's called from a workqueue. I take no blame for this though, you guys
added this function and you also changed ieee80211_set_disassoc() in
ways that made the original implementation wrong :P
John, please apply the patch below.
johannes
From: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Subject: [PATCH] mac80211: fix notify_mac function
The ieee80211_notify_mac() function uses ieee80211_sta_req_auth() which
in turn calls ieee80211_set_disassoc() which calls a few functions that
need to be able to sleep, so ieee80211_notify_mac() cannot use RCU
locking for the interface list and must use rtnl locking instead.
Signed-off-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
---
net/mac80211/mlme.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- everything.orig/net/mac80211/mlme.c 2008-11-11 11:23:09.000000000 +0100
+++ everything/net/mac80211/mlme.c 2008-11-11 11:23:24.000000000 +0100
@@ -2596,14 +2596,14 @@ void ieee80211_notify_mac(struct ieee802
switch (notif_type) {
case IEEE80211_NOTIFY_RE_ASSOC:
- rcu_read_lock();
- list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+ rtnl_lock();
+ list_for_each_entry(sdata, &local->interfaces, list) {
if (sdata->vif.type != NL80211_IFTYPE_STATION)
continue;
ieee80211_sta_req_auth(sdata, &sdata->u.sta);
}
- rcu_read_unlock();
+ rtnl_unlock();
break;
}
}
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