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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Sara Sharon <sara.sharon@intel.com>,
        Luca Coelho <luciano.coelho@intel.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.9 045/105] iwlwifi: mvm: fix kernel panic in case of assert during CSA
Date:   Mon, 14 Dec 2020 18:28:19 +0100
Message-Id: <20201214172557.450802629@linuxfoundation.org>
In-Reply-To: <20201214172555.280929671@linuxfoundation.org>
References: <20201214172555.280929671@linuxfoundation.org>
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From: Sara Sharon <sara.sharon@intel.com>

[ 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@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/iwlwifi.20201107104557.d64de2c17bff.Iedd0d2afa20a2aacba5259a5cae31cb3a119a4eb@changeid
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 34362dc0d4612..f2d65e8384105 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
@@ -3057,7 +3057,7 @@ 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