mac80211: clean up remain-on-channel on interface stop

When any interface goes down, it could be the one that we
were doing a remain-on-channel with. We therefore need to
cancel the remain-on-channel and flush the related work
structs so they don't run after the interface has been
removed or even destroyed.

It's also possible in this case that an off-channel SKB
was never transmitted, so free it if this is the case.
Note that this can also happen if the driver finishes
the off-channel period without ever starting it.

Cc: stable@kernel.org
Reported-by: Nirav Shah <nirav.j2.shah@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 28 insertions, 0 deletions

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index d4c19a7773db..8664111d0566 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -637,6 +637,18 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
                 ieee80211_configure_filter(local);
                 break;
         default:
+                mutex_lock(&local->mtx);
+                if (local->hw_roc_dev == sdata->dev &&
+                    local->hw_roc_channel) {
+                        /* ignore return value since this is racy */
+                        drv_cancel_remain_on_channel(local);
+                        ieee80211_queue_work(&local->hw, &local->hw_roc_done);
+                }
+                mutex_unlock(&local->mtx);
+
+                flush_work(&local->hw_roc_start);
+                flush_work(&local->hw_roc_done);
+
                 flush_work(&sdata->work);
                 /*
                  * When we get here, the interface is marked down.
diff --git a/net/mac80211/offchannel.c b/net/mac80211/offchannel.c
index f054e94901a2..935aa4b6deee 100644
--- a/net/mac80211/offchannel.c
+++ b/net/mac80211/offchannel.c
@@ -234,6 +234,22 @@ static void ieee80211_hw_roc_done(struct work_struct *work)
                 return;
         }
 
+        /* was never transmitted */
+        if (local->hw_roc_skb) {
+                u64 cookie;
+
+                cookie = local->hw_roc_cookie ^ 2;
+
+                cfg80211_mgmt_tx_status(local->hw_roc_dev, cookie,
+                                        local->hw_roc_skb->data,
+                                        local->hw_roc_skb->len, false,
+                                        GFP_KERNEL);
+
+                kfree_skb(local->hw_roc_skb);
+                local->hw_roc_skb = NULL;
+                local->hw_roc_skb_for_status = NULL;
+        }
+
         if (!local->hw_roc_for_tx)
                 cfg80211_remain_on_channel_expired(local->hw_roc_dev,
                                                    local->hw_roc_cookie,