From: Luciano Coelho <[email protected]> In certain conditions, mac80211 may ask us to stop a scan (scheduled or normal) that is not running anymore. This can also happen when we are doing a different type of scan, for instance, mac80211 can ask us to stop a scheduled scan when we are running a normal scan, due to some race conditions. In this case, we would stop the wrong type of scan and leave everything everything in a wrong state.
To fix this, simply ignore scan stop requests for scans types that are not running. Signed-off-by: Luciano Coelho <[email protected]> Reviewed-by: Johannes Berg <[email protected]> Signed-off-by: Emmanuel Grumbach <[email protected]> --- drivers/net/wireless/iwlwifi/mvm/mac80211.c | 33 +++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c index 1ff7ec0..35feebf 100644 --- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c +++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c @@ -2215,7 +2215,19 @@ static void iwl_mvm_mac_cancel_hw_scan(struct ieee80211_hw *hw, mutex_lock(&mvm->mutex); - iwl_mvm_cancel_scan(mvm); + /* Due to a race condition, it's possible that mac80211 asks + * us to stop a hw_scan when it's already stopped. This can + * happen, for instance, if we stopped the scan ourselves, + * called ieee80211_scan_completed() and the userspace called + * cancel scan scan before ieee80211_scan_work() could run. + * To handle that, simply return if the scan is not running. + */ + /* FIXME: for now, we ignore this race for UMAC scans, since + * they don't set the scan_status. + */ + if ((mvm->scan_status == IWL_MVM_SCAN_OS) || + (mvm->fw->ucode_capa.capa[0] & IWL_UCODE_TLV_CAPA_UMAC_SCAN)) + iwl_mvm_cancel_scan(mvm); mutex_unlock(&mvm->mutex); } @@ -2559,12 +2571,29 @@ static int iwl_mvm_mac_sched_scan_stop(struct ieee80211_hw *hw, int ret; mutex_lock(&mvm->mutex); + + /* Due to a race condition, it's possible that mac80211 asks + * us to stop a sched_scan when it's already stopped. This + * can happen, for instance, if we stopped the scan ourselves, + * called ieee80211_sched_scan_stopped() and the userspace called + * stop sched scan scan before ieee80211_sched_scan_stopped_work() + * could run. To handle this, simply return if the scan is + * not running. + */ + /* FIXME: for now, we ignore this race for UMAC scans, since + * they don't set the scan_status. + */ + if (mvm->scan_status != IWL_MVM_SCAN_SCHED && + !(mvm->fw->ucode_capa.capa[0] & IWL_UCODE_TLV_CAPA_UMAC_SCAN)) { + mutex_unlock(&mvm->mutex); + return 0; + } + ret = iwl_mvm_scan_offload_stop(mvm, false); mutex_unlock(&mvm->mutex); iwl_mvm_wait_for_async_handlers(mvm); return ret; - } static int iwl_mvm_mac_set_key(struct ieee80211_hw *hw, -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
