From: Emmanuel Grumbach Date: Mon, 12 Jun 2017 12:10:09 +0000 (+0300) Subject: iwlwifi: mvm: fix a NULL pointer dereference of error in recovery X-Git-Tag: v4.13-rc6~23^2~9^2~5^2~4 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=61dd8a8a6a0c3cbfb6b02ab652c4f4efb93f3d79;p=platform%2Fkernel%2Flinux-exynos.git iwlwifi: mvm: fix a NULL pointer dereference of error in recovery Sometimes, we can have an firmware crash while trying to recover from a previous firmware problem. When that happens, lots of things can go wrong. For example the stations don't get added properly to mvm->fw_id_to_mac_id. Mac80211 tries to stop A-MPDU upon reconfig but in case of a firmware crash we will bail out fairly early and in the end, we won't delete the A-MPDU Rx timeout. When that timer expired after a double firmware crash, we end up dereferencing mvm->fw_id_to_mac_id[sta_id] which is NULL. Fixes: 10b2b2019d81 ("iwlwifi: mvm: add infrastructure for tracking BA session in driver") Signed-off-by: Emmanuel Grumbach Signed-off-by: Luca Coelho --- diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c index 4df5f13..4a6df45 100644 --- a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c +++ b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c @@ -277,6 +277,18 @@ static void iwl_mvm_rx_agg_session_expired(unsigned long data) /* Timer expired */ sta = rcu_dereference(ba_data->mvm->fw_id_to_mac_id[ba_data->sta_id]); + + /* + * sta should be valid unless the following happens: + * The firmware asserts which triggers a reconfig flow, but + * the reconfig fails before we set the pointer to sta into + * the fw_id_to_mac_id pointer table. Mac80211 can't stop + * A-MDPU and hence the timer continues to run. Then, the + * timer expires and sta is NULL. + */ + if (!sta) + goto unlock; + mvm_sta = iwl_mvm_sta_from_mac80211(sta); ieee80211_stop_rx_ba_session_offl(mvm_sta->vif, sta->addr, ba_data->tid);