[PATCH 4.14 63/67] mac80211_hwsim: Timer should be initialized before device registered

Greg Kroah-Hartman
2018-12-11T15:53:37Z

From: Vasyl Vavrychuk <vasyl.vavrychuk@globallogic.com>

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@vger.kernel.org
Signed-off-by: Vasyl Vavrychuk <vasyl.vavrychuk@globallogic.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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
@@ -2698,6 +2698,10 @@ static int mac80211_hwsim_new_radio(stru

wiphy_ext_feature_set(hw->wiphy, NL80211_EXT_FEATURE_CQM_RSSI_LIST);

+ 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",
@@ -2722,10 +2726,6 @@ 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);