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From: Kamal Mostafa <kamal@canonical.com>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        kernel-team@lists.ubuntu.com
Cc: Anilkumar Kolli <akolli@qti.qualcomm.com>,
        Kalle Valo <kvalo@qca.qualcomm.com>,
        Kamal Mostafa <kamal@canonical.com>
Subject: [PATCH 4.2.y-ckt 068/206] ath10k: fix kernel panic, move arvifs list head init before htt init
Date: Thu,  9 Jun 2016 14:14:37 -0700
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4.2.8-ckt12 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Anilkumar Kolli <akolli@qti.qualcomm.com>

commit 4ad24a9d83bd4bf0a85e95bf144e18d3fda4fbf1 upstream.

It is observed that while loading and unloading ath10k modules
in an infinite loop, before ath10k_core_start() completion HTT
rx frames are received, while processing these frames,
dereferencing the arvifs list code is getting hit before
initilizing the arvifs list, causing a kernel panic.

This patch initilizes the arvifs list before initilizing htt.

Fixes the below issue:
 [<bf88b058>] (ath10k_htt_rx_pktlog_completion_handler+0x278/0xd08 [ath10k_core])
 [<bf88b058>] (ath10k_htt_rx_pktlog_completion_handler [ath10k_core])
 [<bf88c0dc>] (ath10k_htt_txrx_compl_task+0x5f4/0xeb0 [ath10k_core])
 [<bf88c0dc>] (ath10k_htt_txrx_compl_task [ath10k_core])
 [<c0234100>] (tasklet_action+0x8c/0xec)
 [<c0234100>] (tasklet_action)
 [<c02337c0>] (__do_softirq+0xf8/0x228)
 [<c02337c0>] (__do_softirq)  [<c0233920>] (run_ksoftirqd+0x30/0x90)
 Code: e5954ad8 e2899008 e1540009 0a00000d (e5943008)
 ---[ end trace 71de5c2e011dbf56 ]---
 Kernel panic - not syncing: Fatal exception in interrupt

Fixes: 500ff9f9389d ("ath10k: implement chanctx API")
Signed-off-by: Anilkumar Kolli <akolli@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/net/wireless/ath/ath10k/core.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
index 59496a9..b67cdec 100644
--- a/drivers/net/wireless/ath/ath10k/core.c
+++ b/drivers/net/wireless/ath/ath10k/core.c
@@ -1214,6 +1214,10 @@ int ath10k_core_start(struct ath10k *ar, enum ath10k_firmware_mode mode)
 		goto err_hif_stop;
 	}
 
+	ar->free_vdev_map = (1LL << ar->max_num_vdevs) - 1;
+
+	INIT_LIST_HEAD(&ar->arvifs);
+
 	/* we don't care about HTT in UTF mode */
 	if (mode == ATH10K_FIRMWARE_MODE_NORMAL) {
 		status = ath10k_htt_setup(&ar->htt);
@@ -1227,10 +1231,6 @@ int ath10k_core_start(struct ath10k *ar, enum ath10k_firmware_mode mode)
 	if (status)
 		goto err_hif_stop;
 
-	ar->free_vdev_map = (1LL << ar->max_num_vdevs) - 1;
-
-	INIT_LIST_HEAD(&ar->arvifs);
-
 	return 0;
 
 err_hif_stop:
-- 
2.7.4