From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from crystal.sipsolutions.net ([195.210.38.204]:41860 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752317AbYBYPb6 (ORCPT ); Mon, 25 Feb 2008 10:31:58 -0500 Message-Id: <20080225153004.876977000@sipsolutions.net> (sfid-20080225_153207_333055_05680667) References: <20080225152740.360393000@sipsolutions.net> Date: Mon, 25 Feb 2008 16:27:42 +0100 From: Johannes Berg To: John Linville Cc: linux-wireless@vger.kernel.org, Luis Carlos Cobo Subject: [PATCH 02/10] mac80211: safely free beacon in ieee80211_if_reinit Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: 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 --- net/mac80211/ieee80211_iface.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- everything.orig/net/mac80211/ieee80211_iface.c 2008-02-23 14:59:28.000000000 +0100 +++ everything/net/mac80211/ieee80211_iface.c 2008-02-24 10:07:16.000000000 +0100 @@ -209,6 +209,7 @@ 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) { @@ -226,7 +227,10 @@ 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--; --