[PATCH 4.19 007/346] iwlwifi: mvm: fix kernel panic in case of assert during CSA

[Greg Kroah-Hartman]

From: Sara Sharon <sara.sharon@xxxxxxxxx>

[ Upstream commit fe56d05ee6c87f6a1a8c7267affd92c9438249cc ]

During CSA, we briefly nullify the phy context, in __iwl_mvm_unassign_vif_chanctx.
In case we have a FW assert right after it, it remains NULL though.
We end up running into endless loop due to mac80211 trying repeatedly to
move us to ASSOC state, and we keep returning -EINVAL. Later down the road
we hit a kernel panic.

Detect and avoid this endless loop.

Signed-off-by: Sara Sharon <sara.sharon@xxxxxxxxx>
Signed-off-by: Luca Coelho <luciano.coelho@xxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/iwlwifi.20201107104557.d64de2c17bff.Iedd0d2afa20a2aacba5259a5cae31cb3a119a4eb@changeid
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
index 525b26e0f65ee..2fad20c845b47 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
@@ -2880,7 +2880,7 @@ static int iwl_mvm_mac_sta_state(struct ieee80211_hw *hw,
 
 	/* this would be a mac80211 bug ... but don't crash */
 	if (WARN_ON_ONCE(!mvmvif->phy_ctxt))
-		return -EINVAL;
+		return test_bit(IWL_MVM_STATUS_HW_RESTART_REQUESTED, &mvm->status) ? 0 : -EINVAL;
 
 	/*
 	 * If we are in a STA removal flow and in DQA mode:
-- 
2.27.0