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authorJohannes Berg <johannes@sipsolutions.net>2007-09-26 15:19:47 +0200
committerDavid S. Miller <davem@sunset.davemloft.net>2007-10-11 01:53:16 +0200
commit53918994b7c8c3bf0af5f641e1f299856799d883 (patch)
tree63338872613d3c08473acfb46c8a57490f85350b /net/mac80211/ieee80211.c
parent[PATCH] mac80211: fix TKIP IV update (diff)
downloadlinux-53918994b7c8c3bf0af5f641e1f299856799d883.tar.xz
linux-53918994b7c8c3bf0af5f641e1f299856799d883.zip
[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>
Diffstat (limited to 'net/mac80211/ieee80211.c')
-rw-r--r--net/mac80211/ieee80211.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index b1180536c335..2501bff0d15e 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -59,10 +59,10 @@ static void ieee80211_configure_filter(struct ieee80211_local *local)
unsigned int changed_flags;
unsigned int new_flags = 0;
- if (local->iff_promiscs)
+ if (atomic_read(&local->iff_promiscs))
new_flags |= FIF_PROMISC_IN_BSS;
- if (local->iff_allmultis)
+ if (atomic_read(&local->iff_allmultis))
new_flags |= FIF_ALLMULTI;
if (local->monitors)
@@ -521,17 +521,17 @@ static void ieee80211_set_multicast_list(struct net_device *dev)
if (allmulti != sdata_allmulti) {
if (dev->flags & IFF_ALLMULTI)
- local->iff_allmultis++;
+ atomic_inc(&local->iff_allmultis);
else
- local->iff_allmultis--;
+ atomic_dec(&local->iff_allmultis);
sdata->flags ^= IEEE80211_SDATA_ALLMULTI;
}
if (promisc != sdata_promisc) {
if (dev->flags & IFF_PROMISC)
- local->iff_promiscs++;
+ atomic_inc(&local->iff_promiscs);
else
- local->iff_promiscs--;
+ atomic_dec(&local->iff_promiscs);
sdata->flags ^= IEEE80211_SDATA_PROMISC;
}