On Mon, 2013-02-11 at 13:07 -0800, Thomas Pedersen wrote:
> +static int
> +ieee80211_mesh_build_beacon(struct ieee80211_if_mesh *ifmsh)
> +{
> + struct beacon_data *bcn;
> + int head_len, tail_len;
> + struct sk_buff *skb;
> + struct ieee80211_mgmt *mgmt;
> + struct ieee80211_chanctx_conf *chanctx_conf;
> + enum ieee80211_band band;
> + u8 *pos;
> + struct ieee80211_sub_if_data *sdata;
> + int hdr_len = offsetof(struct ieee80211_mgmt, u.beacon) +
> + sizeof(mgmt->u.beacon);
> +
> + sdata = container_of(ifmsh, struct ieee80211_sub_if_data, u.mesh);
> + rcu_read_lock();
This is weird since you already did it outside the function?
> + chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
> + band = chanctx_conf->def.chan->band;
could be NULL? I guess not at this point though.
> +static int
> +ieee80211_mesh_rebuild_beacon(struct ieee80211_if_mesh *ifmsh)
> +{
> + struct ieee80211_sub_if_data *sdata;
> + struct beacon_data *old_bcn;
> + int ret;
> + sdata = container_of(ifmsh, struct ieee80211_sub_if_data, u.mesh);
> +
> + rcu_read_lock();
> + old_bcn = rcu_dereference(ifmsh->beacon);
> + ret = ieee80211_mesh_build_beacon(ifmsh);
This looks totally wrong. You must protect the assignment to
ifmsg->beacon by some lock, so then you don't need the rcu_read_lock()
here since you're under that lock, so this should be
rcu_dereference_protected(..., lockdep_is_held(whatever_lock));
> + if (sdata->vif.bss_conf.enable_beacon &&
> + (changed & (BSS_CHANGED_BEACON |
> + BSS_CHANGED_HT |
> + BSS_CHANGED_BASIC_RATES |
> + BSS_CHANGED_BEACON_INT)))
> + if (ieee80211_mesh_rebuild_beacon(&sdata->u.mesh))
> + return;
Does that return make any sense?
> changed |= ieee80211_mps_local_status_update(sdata);
>
> + if (WARN_ON(ieee80211_mesh_build_beacon(ifmsh))) {
no warning for memory allocation failures please
> @@ -694,6 +833,7 @@ 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);
> + kfree_rcu(ifmsh->beacon, rcu_head);
I think you should set it to NULL first, just so it's clearer.
> @@ -883,6 +1023,7 @@ void ieee80211_mesh_init_sdata(struct
> ieee80211_sub_if_data *sdata)
> skb_queue_head_init(&ifmsh->ps.bc_buf);
> spin_lock_init(&ifmsh->mesh_preq_queue_lock);
> spin_lock_init(&ifmsh->sync_offset_lock);
> + RCU_INIT_POINTER(ifmsh->beacon, NULL);
Isn't everything initialized to 0/null?
johannes
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