From 7ca133bc7f9dd5cee2b469eb917bd352be80a690 Mon Sep 17 00:00:00 2001 From: Simon Wunderlich Date: Thu, 21 Nov 2013 18:19:50 +0100 Subject: [PATCH] mac80211: modify beacon using sdata/wdev-lock, not rtnl lock The csa finalize worker needs to change the beacon information (for different modes). These are normally protected under rtnl lock, but the csa finalize worker is called by drivers and should not acquire the RTNL lock. Therefore change access protection for beacons to sdata/wdev lock. Reported-by: Johannes Berg Signed-off-by: Simon Wunderlich [fix sdata_dereference] Signed-off-by: Johannes Berg --- net/mac80211/cfg.c | 20 ++++++++++++-------- net/mac80211/ieee80211_i.h | 3 +++ 2 files changed, 15 insertions(+), 8 deletions(-) diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index 267d3aca9947..4a5c21ed64d1 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -857,7 +857,7 @@ static int ieee80211_set_probe_resp(struct ieee80211_sub_if_data *sdata, if (!resp || !resp_len) return 1; - old = rtnl_dereference(sdata->u.ap.probe_resp); + old = sdata_dereference(sdata->u.ap.probe_resp, sdata); new = kzalloc(sizeof(struct probe_resp) + resp_len, GFP_KERNEL); if (!new) @@ -881,7 +881,8 @@ int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata, int size, err; u32 changed = BSS_CHANGED_BEACON; - old = rtnl_dereference(sdata->u.ap.beacon); + old = sdata_dereference(sdata->u.ap.beacon, sdata); + /* Need to have a beacon head if we don't have one yet */ if (!params->head && !old) @@ -958,7 +959,7 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev, BSS_CHANGED_P2P_PS; int err; - old = rtnl_dereference(sdata->u.ap.beacon); + old = sdata_dereference(sdata->u.ap.beacon, sdata); if (old) return -EALREADY; @@ -1020,7 +1021,8 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev, err = drv_start_ap(sdata->local, sdata); if (err) { - old = rtnl_dereference(sdata->u.ap.beacon); + old = sdata_dereference(sdata->u.ap.beacon, sdata); + if (old) kfree_rcu(old, rcu_head); RCU_INIT_POINTER(sdata->u.ap.beacon, NULL); @@ -1051,7 +1053,7 @@ static int ieee80211_change_beacon(struct wiphy *wiphy, struct net_device *dev, if (sdata->vif.csa_active) return -EBUSY; - old = rtnl_dereference(sdata->u.ap.beacon); + old = sdata_dereference(sdata->u.ap.beacon, sdata); if (!old) return -ENOENT; @@ -1071,10 +1073,10 @@ static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev) struct probe_resp *old_probe_resp; struct cfg80211_chan_def chandef; - old_beacon = rtnl_dereference(sdata->u.ap.beacon); + old_beacon = sdata_dereference(sdata->u.ap.beacon, sdata); if (!old_beacon) return -ENOENT; - old_probe_resp = rtnl_dereference(sdata->u.ap.probe_resp); + old_probe_resp = sdata_dereference(sdata->u.ap.probe_resp, sdata); /* abort any running channel switch */ sdata->vif.csa_active = false; @@ -1975,7 +1977,7 @@ static int ieee80211_change_bss(struct wiphy *wiphy, enum ieee80211_band band; u32 changed = 0; - if (!rtnl_dereference(sdata->u.ap.beacon)) + if (!sdata_dereference(sdata->u.ap.beacon, sdata)) return -ENOENT; band = ieee80211_get_sdata_band(sdata); @@ -3045,6 +3047,8 @@ static int ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev, struct ieee80211_if_mesh __maybe_unused *ifmsh; int err, num_chanctx; + lockdep_assert_held(&sdata->wdev.mtx); + if (!list_empty(&local->roc_list) || local->scanning) return -EBUSY; diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 834f0eb3e420..32bae218d6e5 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -813,6 +813,9 @@ static inline void sdata_unlock(struct ieee80211_sub_if_data *sdata) __release(&sdata->wdev.mtx); } +#define sdata_dereference(p, sdata) \ + rcu_dereference_protected(p, lockdep_is_held(&sdata->wdev.mtx)) + static inline void sdata_assert_lock(struct ieee80211_sub_if_data *sdata) { -- 2.20.1