@@ -1051,7 +1051,7 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
local->hw.wiphy->signal_type = CFG80211_SIGNAL_TYPE_UNSPEC;
if (hw->max_signal <= 0) {
result = -EINVAL;
- goto fail_wiphy_register;
+ goto fail_workqueue;
}
}
@@ -1113,7 +1113,7 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
result = ieee80211_init_cipher_suites(local);
if (result < 0)
- goto fail_wiphy_register;
+ goto fail_workqueue;
if (!local->ops->remain_on_channel)
local->hw.wiphy->max_remain_on_channel_duration = 5000;
@@ -1139,10 +1139,6 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
local->hw.wiphy->max_num_csa_counters = IEEE80211_MAX_CSA_COUNTERS_NUM;
- result = wiphy_register(local->hw.wiphy);
- if (result < 0)
- goto fail_wiphy_register;
-
/*
* We use the number of queues for feature tests (QoS, HT) internally
* so restrict them appropriately.
@@ -1254,6 +1250,14 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
local->sband_allocated |= BIT(band);
}
+ rtnl_unlock();
+
+ result = wiphy_register(local->hw.wiphy);
+ if (result < 0)
+ goto fail_wiphy_register;
+
+ rtnl_lock();
+
/* add one default STA interface if supported */
if (local->hw.wiphy->interface_modes & BIT(NL80211_IFTYPE_STATION) &&
!ieee80211_hw_check(hw, NO_AUTO_VIF)) {
@@ -1293,6 +1297,8 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
#if defined(CONFIG_INET) || defined(CONFIG_IPV6)
fail_ifa:
#endif
+ wiphy_unregister(local->hw.wiphy);
+ fail_wiphy_register:
rtnl_lock();
rate_control_deinitialize(local);
ieee80211_remove_interfaces(local);
@@ -1302,8 +1308,6 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
ieee80211_led_exit(local);
destroy_workqueue(local->workqueue);
fail_workqueue:
- wiphy_unregister(local->hw.wiphy);
- fail_wiphy_register:
if (local->wiphy_ciphers_allocated)
kfree(local->hw.wiphy->cipher_suites);
kfree(local->int_scan_req);
@@ -1353,8 +1357,8 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
skb_queue_purge(&local->skb_queue_unreliable);
skb_queue_purge(&local->skb_queue_tdls_chsw);
- destroy_workqueue(local->workqueue);
wiphy_unregister(local->hw.wiphy);
+ destroy_workqueue(local->workqueue);
ieee80211_led_exit(local);
kfree(local->int_scan_req);
}
A race condition leading to a kernel crash is observed during invocation of ieee80211_register_hw() on a dragonboard410c device having wcn36xx driver built as a loadable module along with a wifi manager in user-space waiting for a wifi device (wlanX) to be active. Sequence diagram for a particular kernel crash scenario: user-space ieee80211_register_hw() RX IRQ +++++++++++++++++++++++++++++++++++++++++++++ | | | |<---wlan0---wiphy_register() | |----start wlan0---->| | | |<---IRQ---(RX packet) | Kernel crash | | due to unallocated | | workqueue. | | | | | alloc_ordered_workqueue() | | | | | Misc wiphy init. | | | | | ieee80211_if_add() | | | | As evident from above sequence diagram, this race condition isn't specific to a particular wifi driver but rather the initialization sequence in ieee80211_register_hw() needs to be fixed. So re-order the initialization sequence and the updated sequence diagram would look like: user-space ieee80211_register_hw() RX IRQ +++++++++++++++++++++++++++++++++++++++++++++ | | | | alloc_ordered_workqueue() | | | | | Misc wiphy init. | | | | |<---wlan0---wiphy_register() | |----start wlan0---->| | | |<---IRQ---(RX packet) | | | | ieee80211_if_add() | | | | Cc: <stable@vger.kernel.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> --- net/mac80211/main.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-)