[PATCH AUTOSEL 5.1 060/375] iwlwifi: pcie: don't crash on invalid RX interrupt

[Sasha Levin <sashal@kernel.org>]

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

[ Upstream commit 30f24eabab8cd801064c5c37589d803cb4341929 ]

If for some reason the device gives us an RX interrupt before we're
ready for it, perhaps during device power-on with misconfigured IRQ
causes mapping or so, we can crash trying to access the queues.

Prevent that by checking that we actually have RXQs and that they
were properly allocated.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
index 8d4f0628622bb..12f02aaf923ed 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
@@ -1434,10 +1434,15 @@ static struct iwl_rx_mem_buffer *iwl_pcie_get_rxb(struct iwl_trans *trans,
 static void iwl_pcie_rx_handle(struct iwl_trans *trans, int queue)
 {
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
-	struct iwl_rxq *rxq = &trans_pcie->rxq[queue];
+	struct iwl_rxq *rxq;
 	u32 r, i, count = 0;
 	bool emergency = false;
 
+	if (WARN_ON_ONCE(!trans_pcie->rxq || !trans_pcie->rxq[queue].bd))
+		return;
+
+	rxq = &trans_pcie->rxq[queue];
+
 restart:
 	spin_lock(&rxq->lock);
 	/* uCode's read index (stored in shared DRAM) indicates the last Rx
-- 
2.20.1