mac80211: fix deadlock in sta->lock
This patch fixes a deadlock of sta->lock use, occurring while changing
tx aggregation states, as dev_queue_xmit end up in new function
test_and_clear_sta_flags that uses that lock thus leading to deadlock
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 97d4a53..f79f6b9 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -589,8 +589,8 @@
sta = sta_info_get(local, ra);
if (!sta) {
printk(KERN_DEBUG "Could not find the station\n");
- rcu_read_unlock();
- return -ENOENT;
+ ret = -ENOENT;
+ goto exit;
}
spin_lock_bh(&sta->lock);
@@ -598,7 +598,7 @@
/* we have tried too many times, receiver does not want A-MPDU */
if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
ret = -EBUSY;
- goto start_ba_exit;
+ goto err_unlock_sta;
}
state = &sta->ampdu_mlme.tid_state_tx[tid];
@@ -609,7 +609,7 @@
"idle on tid %u\n", tid);
#endif /* CONFIG_MAC80211_HT_DEBUG */
ret = -EAGAIN;
- goto start_ba_exit;
+ goto err_unlock_sta;
}
/* prepare A-MPDU MLME for Tx aggregation */
@@ -620,7 +620,7 @@
printk(KERN_ERR "allocate tx mlme to tid %d failed\n",
tid);
ret = -ENOMEM;
- goto start_ba_exit;
+ goto err_unlock_sta;
}
/* Tx timer */
sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.function =
@@ -643,7 +643,7 @@
printk(KERN_DEBUG "BA request denied - queue unavailable for"
" tid %d\n", tid);
#endif /* CONFIG_MAC80211_HT_DEBUG */
- goto start_ba_err;
+ goto err_unlock_queue;
}
sdata = sta->sdata;
@@ -665,12 +665,13 @@
" tid %d\n", tid);
#endif /* CONFIG_MAC80211_HT_DEBUG */
*state = HT_AGG_STATE_IDLE;
- goto start_ba_err;
+ goto err_unlock_queue;
}
/* Will put all the packets in the new SW queue */
ieee80211_requeue(local, ieee802_1d_to_ac[tid]);
spin_unlock_bh(&local->mdev->queue_lock);
+ spin_unlock_bh(&sta->lock);
/* send an addBA request */
sta->ampdu_mlme.dialog_token_allocator++;
@@ -678,25 +679,26 @@
sta->ampdu_mlme.dialog_token_allocator;
sta->ampdu_mlme.tid_tx[tid]->ssn = start_seq_num;
+
ieee80211_send_addba_request(sta->sdata->dev, ra, tid,
sta->ampdu_mlme.tid_tx[tid]->dialog_token,
sta->ampdu_mlme.tid_tx[tid]->ssn,
0x40, 5000);
-
/* activate the timer for the recipient's addBA response */
sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.expires =
jiffies + ADDBA_RESP_INTERVAL;
add_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);
printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
- goto start_ba_exit;
+ goto exit;
-start_ba_err:
+err_unlock_queue:
kfree(sta->ampdu_mlme.tid_tx[tid]);
sta->ampdu_mlme.tid_tx[tid] = NULL;
spin_unlock_bh(&local->mdev->queue_lock);
ret = -EBUSY;
-start_ba_exit:
+err_unlock_sta:
spin_unlock_bh(&sta->lock);
+exit:
rcu_read_unlock();
return ret;
}
@@ -835,10 +837,11 @@
}
state = &sta->ampdu_mlme.tid_state_tx[tid];
- spin_lock_bh(&sta->lock);
+ /* NOTE: no need to use sta->lock in this state check, as
+ * ieee80211_stop_tx_ba_session will let only
+ * one stop call to pass through per sta/tid */
if ((*state & HT_AGG_STATE_REQ_STOP_BA_MSK) == 0) {
printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
- spin_unlock_bh(&sta->lock);
rcu_read_unlock();
return;
}
@@ -861,6 +864,7 @@
* ieee80211_wake_queue is not used here as this queue is not
* necessarily stopped */
netif_schedule(local->mdev);
+ spin_lock_bh(&sta->lock);
*state = HT_AGG_STATE_IDLE;
sta->ampdu_mlme.addba_req_num[tid] = 0;
kfree(sta->ampdu_mlme.tid_tx[tid]);