[PATCH 2/8] mac80211: safely free beacon in ieee80211_if_reinit
From: Johannes Berg <johannes@sipsolutions.net>
Date: 2008-02-22 14:08:10
If ieee80211_if_reinit() is called from ieee80211_unregister_hw() then it is possible that the driver will still request a beacon (it is allowed to until ieee80211_unregister_hw() has returned.) This means we need to use an RCU-protected write to the beacon information even in this function. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> --- net/mac80211/ieee80211_iface.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- everything.orig/net/mac80211/ieee80211_iface.c 2008-02-21 14:35:24.000000000 +0100
+++ everything/net/mac80211/ieee80211_iface.c 2008-02-21 15:13:17.000000000 +0100@@ -193,6 +193,7 @@ void ieee80211_if_reinit(struct net_devi /* Remove all virtual interfaces that use this BSS * as their sdata->bss */ struct ieee80211_sub_if_data *tsdata, *n; + struct beacon_data *beacon; list_for_each_entry_safe(tsdata, n, &local->interfaces, list) { if (tsdata != sdata && tsdata->bss == &sdata->u.ap) {
@@ -210,7 +211,10 @@ void ieee80211_if_reinit(struct net_devi } } - kfree(sdata->u.ap.beacon); + beacon = sdata->u.ap.beacon; + rcu_assign_pointer(sdata->u.ap.beacon, NULL); + synchronize_rcu(); + kfree(beacon); while ((skb = skb_dequeue(&sdata->u.ap.ps_bc_buf))) { local->total_ps_buffered--;
--