Return-path: Received: from mail-pd0-f177.google.com ([209.85.192.177]:63182 "EHLO mail-pd0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752274Ab3FJUTu (ORCPT ); Mon, 10 Jun 2013 16:19:50 -0400 Received: by mail-pd0-f177.google.com with SMTP id p10so2306454pdj.36 for ; Mon, 10 Jun 2013 13:19:50 -0700 (PDT) From: Thomas Pedersen To: Johannes Berg Cc: linux-wireless , open80211s , Bob Copeland , Thomas Pedersen Subject: [PATCH v2 1/2] mac80211: fix mesh deadlock Date: Mon, 10 Jun 2013 13:17:21 -0700 Message-Id: <1370895442-21784-1-git-send-email-thomas@cozybit.com> (sfid-20130610_221954_862723_54F55330) Sender: linux-wireless-owner@vger.kernel.org List-ID: The patch "cfg80211/mac80211: use cfg80211 wdev mutex in mac80211" introduced several deadlocks by converting the ifmsh->mtx to wdev->mtx. Solve these by: 1. drop the cancel_work_sync() in ieee80211_stop_mesh(). Instead make the mesh work conditional on whether the mesh is running or not. 2. lock the mesh work with sdata_lock() to protect beacon updates and prevent races with wdev->mesh_id_len or cfg80211. Signed-off-by: Thomas Pedersen --- net/mac80211/mesh.c | 29 +++++++++++++++++------------ net/mac80211/mesh_plink.c | 7 +------ 2 files changed, 18 insertions(+), 18 deletions(-) diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c index 73a597b..d5faf91 100644 --- a/net/mac80211/mesh.c +++ b/net/mac80211/mesh.c @@ -579,9 +579,7 @@ static void ieee80211_mesh_housekeeping(struct ieee80211_sub_if_data *sdata) mesh_path_expire(sdata); changed = mesh_accept_plinks_update(sdata); - sdata_lock(sdata); ieee80211_mbss_info_change_notify(sdata, changed); - sdata_unlock(sdata); mod_timer(&ifmsh->housekeeping_timer, round_jiffies(jiffies + @@ -788,12 +786,10 @@ void ieee80211_stop_mesh(struct ieee80211_sub_if_data *sdata) sdata->vif.bss_conf.enable_beacon = false; clear_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED, &sdata->state); ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON_ENABLED); - sdata_lock(sdata); bcn = rcu_dereference_protected(ifmsh->beacon, lockdep_is_held(&sdata->wdev.mtx)); rcu_assign_pointer(ifmsh->beacon, NULL); kfree_rcu(bcn, rcu_head); - sdata_unlock(sdata); /* flush STAs and mpaths on this iface */ sta_info_flush(sdata); @@ -806,14 +802,6 @@ void ieee80211_stop_mesh(struct ieee80211_sub_if_data *sdata) del_timer_sync(&sdata->u.mesh.housekeeping_timer); del_timer_sync(&sdata->u.mesh.mesh_path_root_timer); del_timer_sync(&sdata->u.mesh.mesh_path_timer); - /* - * If the timer fired while we waited for it, it will have - * requeued the work. Now the work will be running again - * but will not rearm the timer again because it checks - * whether the interface is running, which, at this point, - * it no longer is. - */ - cancel_work_sync(&sdata->work); local->fif_other_bss--; atomic_dec(&local->iff_allmultis); @@ -954,6 +942,12 @@ void ieee80211_mesh_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt; u16 stype; + sdata_lock(sdata); + + /* mesh already went down */ + if (!sdata->wdev.mesh_id_len) + goto out; + rx_status = IEEE80211_SKB_RXCB(skb); mgmt = (struct ieee80211_mgmt *) skb->data; stype = le16_to_cpu(mgmt->frame_control) & IEEE80211_FCTL_STYPE; @@ -971,12 +965,20 @@ void ieee80211_mesh_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata, ieee80211_mesh_rx_mgmt_action(sdata, mgmt, skb->len, rx_status); break; } +out: + sdata_unlock(sdata); } void ieee80211_mesh_work(struct ieee80211_sub_if_data *sdata) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; + sdata_lock(sdata); + + /* mesh already went down */ + if (!sdata->wdev.mesh_id_len) + goto out; + if (ifmsh->preq_queue_len && time_after(jiffies, ifmsh->last_preq + msecs_to_jiffies(ifmsh->mshcfg.dot11MeshHWMPpreqMinInterval))) @@ -996,6 +998,9 @@ void ieee80211_mesh_work(struct ieee80211_sub_if_data *sdata) if (test_and_clear_bit(MESH_WORK_DRIFT_ADJUST, &ifmsh->wrkq_flags)) mesh_sync_adjust_tbtt(sdata); + +out: + sdata_unlock(sdata); } void ieee80211_mesh_notify_scan_completed(struct ieee80211_local *local) diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c index 6c4da99..09bebed 100644 --- a/net/mac80211/mesh_plink.c +++ b/net/mac80211/mesh_plink.c @@ -517,9 +517,7 @@ void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata, ieee80211_mps_frame_release(sta, elems); out: rcu_read_unlock(); - sdata_lock(sdata); ieee80211_mbss_info_change_notify(sdata, changed); - sdata_unlock(sdata); } static void mesh_plink_timer(unsigned long data) @@ -1070,9 +1068,6 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, rcu_read_unlock(); - if (changed) { - sdata_lock(sdata); + if (changed) ieee80211_mbss_info_change_notify(sdata, changed); - sdata_unlock(sdata); - } } -- 1.7.10.4