From 3dd1cd2d33d94fd56228b9a7f7b467ceccae8f4d Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 2 Oct 2013 12:05:24 +0200 Subject: [PATCH] iwlwifi: mvm: fix locking in iwl_mvm_bt_rssi_event() This will deadlock due to commit 9f34783863bea806 ("iwlwifi: mvm: Implement BT coex notifications"): ============================================= [ INFO: possible recursive locking detected ] 3.5.0 #10 Tainted: G W O --------------------------------------------- kworker/2:1/5214 is trying to acquire lock: (&mvm->mutex){+.+.+.}, at: [] iwl_mvm_bt_rssi_event+0x5e/0x210 [iwlmvm] but task is already holding lock: (&mvm->mutex){+.+.+.}, at: [] iwl_mvm_async_handlers_wk+0x49/0x120 [iwlmvm] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&mvm->mutex); lock(&mvm->mutex); *** DEADLOCK *** Change-Id: I9104f252b34676e2f7ffcd51166f95367e08a4d9 Signed-off-by: Johannes Berg Reviewed-on: https://gerrit.rds.intel.com/21887 Reviewed-by: Emmanuel Grumbach Tested-by: Emmanuel Grumbach Signed-off-by: Johannes Berg Conflicts: drivers/net/wireless/iwlwifi/mvm/bt-coex.c --- drivers/net/wireless/iwlwifi/mvm/bt-coex.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/mvm/bt-coex.c b/drivers/net/wireless/iwlwifi/mvm/bt-coex.c index bba5947fd652..ef59f8412bd1 100644 --- a/drivers/net/wireless/iwlwifi/mvm/bt-coex.c +++ b/drivers/net/wireless/iwlwifi/mvm/bt-coex.c @@ -602,15 +602,15 @@ void iwl_mvm_bt_rssi_event(struct iwl_mvm *mvm, struct ieee80211_vif *vif, }; int ret; - mutex_lock(&mvm->mutex); + lockdep_assert_held(&mvm->mutex); /* Rssi update while not associated ?! */ if (WARN_ON_ONCE(mvmvif->ap_sta_id == IWL_MVM_STATION_COUNT)) - goto out_unlock; + return; /* No open connection - reports should be disabled */ if (!BT_MBOX_MSG(&mvm->last_bt_notif, 3, OPEN_CON_2)) - goto out_unlock; + return; IWL_DEBUG_COEX(mvm, "RSSI for %pM is now %s\n", vif->bss_conf.bssid, rssi_event == RSSI_EVENT_HIGH ? "HIGH" : "LOW"); @@ -641,9 +641,6 @@ void iwl_mvm_bt_rssi_event(struct iwl_mvm *mvm, struct ieee80211_vif *vif, if (iwl_mvm_bt_udpate_ctrl_kill_msk(mvm, data.reduced_tx_power)) IWL_ERR(mvm, "Failed to update the ctrl_kill_msk\n"); - - out_unlock: - mutex_unlock(&mvm->mutex); } void iwl_mvm_bt_coex_vif_assoc(struct iwl_mvm *mvm, struct ieee80211_vif *vif)