From:   Luca Coelho <luca@coelho.fi>
To:     kvalo@codeaurora.org
Cc:     linux-wireless@vger.kernel.org,
        Johannes Berg <johannes.berg@intel.com>,
        Luca Coelho <luciano.coelho@intel.com>
Date:   Fri, 22 Mar 2019 14:47:42 +0200
Message-Id: <20190322124744.17924-2-luca@coelho.fi>
In-Reply-To: <20190322124744.17924-1-luca@coelho.fi>
References: <20190322124744.17924-1-luca@coelho.fi>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Subject: [PATCH 1/3] iwlwifi: mvm: avoid possible deadlock in TX path
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

From: Johannes Berg <johannes.berg@intel.com>

iwl_mvm_tx_mpdu() may run from iwl_mvm_add_new_dqa_stream_wk(), where
soft-IRQs aren't disabled. In this case, it may hold the station lock
and be interrupted by a soft-IRQ that also wants to acquire said lock,
leading to a deadlock.

Fix it by disabling soft-IRQs in iwl_mvm_add_new_dqa_stream_wk().

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
---
 drivers/net/wireless/intel/iwlwifi/mvm/sta.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
index db26f0041a81..98d123dd7177 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
@@ -1399,7 +1399,9 @@ void iwl_mvm_add_new_dqa_stream_wk(struct work_struct *wk)
 
 		iwl_mvm_sta_alloc_queue(mvm, txq->sta, txq->ac, tid);
 		list_del_init(&mvmtxq->list);
+		local_bh_disable();
 		iwl_mvm_mac_itxq_xmit(mvm->hw, txq);
+		local_bh_enable();
 	}
 
 	mutex_unlock(&mvm->mutex);
-- 
2.20.1