[PATCH 4.9 45/51] mac80211_hwsim: Timer should be initialized before device registered

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Vasyl Vavrychuk <vasyl.vavrychuk@xxxxxxxxxxxxxxx>

commit a1881c9b8a1edef0a5ae1d5c1b61406fe3402114 upstream.

Otherwise if network manager starts configuring Wi-Fi interface
immidiatelly after getting notification of its creation, we will get
NULL pointer dereference:

  BUG: unable to handle kernel NULL pointer dereference at           (null)
  IP: [<ffffffff95ae94c8>] hrtimer_active+0x28/0x50
  ...
  Call Trace:
   [<ffffffff95ae9997>] ? hrtimer_try_to_cancel+0x27/0x110
   [<ffffffff95ae9a95>] ? hrtimer_cancel+0x15/0x20
   [<ffffffffc0803bf0>] ? mac80211_hwsim_config+0x140/0x1c0 [mac80211_hwsim]

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Vasyl Vavrychuk <vasyl.vavrychuk@xxxxxxxxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/net/wireless/mac80211_hwsim.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -2633,6 +2633,10 @@ static int mac80211_hwsim_new_radio(stru
 	if (param->no_vif)
 		ieee80211_hw_set(hw, NO_AUTO_VIF);
 
+	tasklet_hrtimer_init(&data->beacon_timer,
+			     mac80211_hwsim_beacon,
+			     CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+
 	err = ieee80211_register_hw(hw);
 	if (err < 0) {
 		printk(KERN_DEBUG "mac80211_hwsim: ieee80211_register_hw failed (%d)\n",
@@ -2657,10 +2661,6 @@ static int mac80211_hwsim_new_radio(stru
 				    data->debugfs,
 				    data, &hwsim_simulate_radar);
 
-	tasklet_hrtimer_init(&data->beacon_timer,
-			     mac80211_hwsim_beacon,
-			     CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
-
 	spin_lock_bh(&hwsim_radio_lock);
 	list_add_tail(&data->list, &hwsim_radios);
 	spin_unlock_bh(&hwsim_radio_lock);