[PATCH] mac80211: fix iff_promiscs, iff_allmultis race
When we update the counters iff_promiscs and iff_allmultis
in struct ieee80211_local we have no common lock held to
protect them. The problem is that the update to each counter
may not be atomic, so we could end up with iff_promiscs == -1
in unfortunate conditions. To fix it, use atomic_t values.
It doesn't matter whether the two counters are updated
together atomically or not, if there are two invocations
of set_multicast_list we will end up with multiple
configure_filter() invocations of which the latter will always
be correct.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 34adc52..03635fb 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1531,7 +1531,8 @@
skb = rx.skb;
if (sta && !(sta->flags & (WLAN_STA_WDS | WLAN_STA_ASSOC_AP)) &&
- !local->iff_promiscs && !is_multicast_ether_addr(hdr->addr1)) {
+ !atomic_read(&local->iff_promiscs) &&
+ !is_multicast_ether_addr(hdr->addr1)) {
rx.flags |= IEEE80211_TXRXD_RXRA_MATCH;
ieee80211_invoke_rx_handlers(local, local->rx_handlers, &rx,
rx.sta);