diff options
| author | Johannes Berg <johannes@sipsolutions.net> | 2007-09-26 15:19:47 +0200 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-10-10 16:53:16 -0700 |
| commit | 53918994b7c8c3bf0af5f641e1f299856799d883 (patch) | |
| tree | 63338872613d3c08473acfb46c8a57490f85350b /net/mac80211 | |
| parent | 50741ae05a4742cae99361f57d84b5f8d33822a4 (diff) | |
| download | linux-53918994b7c8c3bf0af5f641e1f299856799d883.tar.bz2 | |
[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')
| -rw-r--r-- | net/mac80211/ieee80211.c | 12 | ||||
| -rw-r--r-- | net/mac80211/ieee80211_i.h | 5 | ||||
| -rw-r--r-- | net/mac80211/rx.c | 3 |
3 files changed, 10 insertions, 10 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; } diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 32d19bbf522c..38e0a467fa8e 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -444,9 +444,8 @@ struct ieee80211_local { struct ieee80211_tx_stored_packet pending_packet[NUM_TX_DATA_QUEUES]; struct tasklet_struct tx_pending_tasklet; - int mc_count; /* total count of multicast entries in all interfaces */ - int iff_allmultis, iff_promiscs; - /* number of interfaces with corresponding IFF_ flags */ + /* number of interfaces with corresponding IFF_ flags */ + atomic_t iff_allmultis, iff_promiscs; struct rate_control_ref *rate_ctrl; diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 34adc5288fbc..03635fb3e9b6 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -1531,7 +1531,8 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb, 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); |