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mac80211: fix mesh deadlock

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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 <thomas@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Thomas Pedersen 2013-06-10 13:17:21 -07:00 committed by Johannes Berg
parent 780b40df12
commit ecccd072b0
2 changed files with 18 additions and 18 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

29
net/mac80211/mesh.c
View file

@ -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)

7
net/mac80211/mesh_plink.c
View file

@ -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);
}
}