Return-path: Received: from s3.sipsolutions.net ([5.9.151.49]:38624 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751057AbbCERHY (ORCPT ); Thu, 5 Mar 2015 12:07:24 -0500 From: Johannes Berg To: linux-wireless@vger.kernel.org Cc: Sven Eckelmann , Felix Fietkau , Johannes Berg Subject: [RFC v2] [RFC] mac80211: lock rate control Date: Thu, 5 Mar 2015 18:07:17 +0100 Message-Id: <1425575237-5556-1-git-send-email-johannes@sipsolutions.net> (sfid-20150305_180727_777641_0F98BD69) Sender: linux-wireless-owner@vger.kernel.org List-ID: From: Johannes Berg Both minstrel (reported by Sven Eckelmann) and the iwlwifi rate control aren't properly taking concurrency into account. It's likely that the same is true for other rate control algorithms. In the case of minstrel this manifests itself in crashes when an update and other data access are run concurrently, for example when the stations change bandwidth or similar. In iwlwifi, this can cause firmware crashes. Since fixing all rate control algorithms will be very difficult, just provide locking for invocations. This protects the internal data structures the algorithms maintain. I've manipulated hostapd to test this, by having it change its advertised bandwidth roughly ever 150ms. At the same time, I'm running a flood ping between the client and the AP, which causes this race of update vs. get_rate/status to easily happen on the client. With this change, the system survives this test. Change-Id: I77383401a67a1ec380cec65b34802ab879357e80 Reported-by: Sven Eckelmann Signed-off-by: Johannes Berg --- net/mac80211/rate.c | 8 +++++++- net/mac80211/rate.h | 12 +++++++++--- net/mac80211/sta_info.c | 2 +- net/mac80211/sta_info.h | 1 + 4 files changed, 18 insertions(+), 5 deletions(-) diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c index bc5270ed26bd..68bed2cad6f3 100644 --- a/net/mac80211/rate.c +++ b/net/mac80211/rate.c @@ -683,7 +683,13 @@ void rate_control_get_rate(struct ieee80211_sub_if_data *sdata, if (sdata->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) return; - ref->ops->get_rate(ref->priv, ista, priv_sta, txrc); + if (ista) { + spin_lock_bh(&sta->rate_ctrl_lock); + ref->ops->get_rate(ref->priv, ista, priv_sta, txrc); + spin_unlock_bh(&sta->rate_ctrl_lock); + } else { + ref->ops->get_rate(ref->priv, NULL, NULL, txrc); + } if (sdata->local->hw.flags & IEEE80211_HW_SUPPORTS_RC_TABLE) return; diff --git a/net/mac80211/rate.h b/net/mac80211/rate.h index a7d5439322d7..d0ecc8952fa0 100644 --- a/net/mac80211/rate.h +++ b/net/mac80211/rate.h @@ -42,10 +42,12 @@ static inline void rate_control_tx_status(struct ieee80211_local *local, if (!ref || !test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) return; + spin_lock_bh(&sta->rate_ctrl_lock); if (ref->ops->tx_status) ref->ops->tx_status(ref->priv, sband, ista, priv_sta, skb); else ref->ops->tx_status_noskb(ref->priv, sband, ista, priv_sta, info); + spin_unlock_bh(&sta->rate_ctrl_lock); } static inline void @@ -64,7 +66,9 @@ rate_control_tx_status_noskb(struct ieee80211_local *local, if (WARN_ON_ONCE(!ref->ops->tx_status_noskb)) return; + spin_lock_bh(&sta->rate_ctrl_lock); ref->ops->tx_status_noskb(ref->priv, sband, ista, priv_sta, info); + spin_unlock_bh(&sta->rate_ctrl_lock); } static inline void rate_control_rate_init(struct sta_info *sta) @@ -115,18 +119,20 @@ static inline void rate_control_rate_update(struct ieee80211_local *local, return; } + spin_lock_bh(&sta->rate_ctrl_lock); ref->ops->rate_update(ref->priv, sband, &chanctx_conf->def, ista, priv_sta, changed); + spin_unlock_bh(&sta->rate_ctrl_lock); rcu_read_unlock(); } drv_sta_rc_update(local, sta->sdata, &sta->sta, changed); } static inline void *rate_control_alloc_sta(struct rate_control_ref *ref, - struct ieee80211_sta *sta, - gfp_t gfp) + struct sta_info *sta, gfp_t gfp) { - return ref->ops->alloc_sta(ref->priv, sta, gfp); + spin_lock_init(&sta->rate_ctrl_lock); + return ref->ops->alloc_sta(ref->priv, &sta->sta, gfp); } static inline void rate_control_free_sta(struct sta_info *sta) diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c index 11c1e71c833d..eab8d8afab13 100644 --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -292,7 +292,7 @@ static int sta_prepare_rate_control(struct ieee80211_local *local, sta->rate_ctrl = local->rate_ctrl; sta->rate_ctrl_priv = rate_control_alloc_sta(sta->rate_ctrl, - &sta->sta, gfp); + sta, gfp); if (!sta->rate_ctrl_priv) return -ENOMEM; diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h index 36a14a0be6dd..b53c6ca3179a 100644 --- a/net/mac80211/sta_info.h +++ b/net/mac80211/sta_info.h @@ -396,6 +396,7 @@ struct sta_info { u8 ptk_idx; struct rate_control_ref *rate_ctrl; void *rate_ctrl_priv; + spinlock_t rate_ctrl_lock; spinlock_t lock; struct work_struct drv_deliver_wk; -- 2.1.4