[PATCH AUTOSEL 4.9 01/64] ath10k: fix kernel panic by moving pci flush after napi_disable

[PATCH AUTOSEL 4.9 01/64] ath10k: fix kernel panic by moving pci flush after napi_disable

[Sasha Levin]

From: Tamizh chelvam <tamizhr@codeaurora.org>

[ Upstream commit bd1d395070cca4f42a93e520b0597274789274a4 ]

When continuously running wifi up/down sequence, the napi poll
can be scheduled after the CE buffers being freed by ath10k_pci_flush

Steps:
  In a certain condition, during wifi down below scenario might occur.

ath10k_stop->ath10k_hif_stop->napi_schedule->ath10k_pci_flush->napi_poll(napi_synchronize).

In the above scenario, CE buffer entries will be freed up and become NULL in
ath10k_pci_flush. And the napi_poll has been invoked after the flush process
and it will try to get the skb from the CE buffer entry and perform some action on that.
Since the CE buffer already cleaned by pci flush this action will create NULL
pointer dereference and trigger below kernel panic.

Unable to handle kernel NULL pointer dereference at virtual address 0000005c
PC is at ath10k_pci_htt_rx_cb+0x64/0x3ec [ath10k_pci]
ath10k_pci_htt_rx_cb [ath10k_pci]
ath10k_ce_per_engine_service+0x74/0xc4 [ath10k_pci]
ath10k_ce_per_engine_service [ath10k_pci]
ath10k_ce_per_engine_service_any+0x74/0x80 [ath10k_pci]
ath10k_ce_per_engine_service_any [ath10k_pci]
ath10k_pci_napi_poll+0x48/0xec [ath10k_pci]
ath10k_pci_napi_poll [ath10k_pci]
net_rx_action+0xac/0x160
net_rx_action
__do_softirq+0xdc/0x208
__do_softirq
irq_exit+0x84/0xe0
irq_exit
__handle_domain_irq+0x80/0xa0
__handle_domain_irq
gic_handle_irq+0x38/0x5c
gic_handle_irq
__irq_usr+0x44/0x60

Tested on QCA4019 and firmware version 10.4.3.2.1.1-00010

Signed-off-by: Tamizh chelvam <tamizhr@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/ath/ath10k/ahb.c | 4 ++--
 drivers/net/wireless/ath/ath10k/pci.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/ahb.c b/drivers/net/wireless/ath/ath10k/ahb.c
index da770af830369..125b5c31b2b0a 100644
--- a/drivers/net/wireless/ath/ath10k/ahb.c
+++ b/drivers/net/wireless/ath/ath10k/ahb.c
@@ -658,10 +658,10 @@ static void ath10k_ahb_hif_stop(struct ath10k *ar)
 	ath10k_ahb_irq_disable(ar);
 	synchronize_irq(ar_ahb->irq);
 
-	ath10k_pci_flush(ar);
-
 	napi_synchronize(&ar->napi);
 	napi_disable(&ar->napi);
+
+	ath10k_pci_flush(ar);
 }
 
 static int ath10k_ahb_hif_power_up(struct ath10k *ar)
diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index 25b8d501d437e..b7bac14d1487b 100644
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/drivers/net/wireless/ath/ath10k/pci.c
@@ -1781,9 +1781,9 @@ static void ath10k_pci_hif_stop(struct ath10k *ar)
 
 	ath10k_pci_irq_disable(ar);
 	ath10k_pci_irq_sync(ar);
-	ath10k_pci_flush(ar);
 	napi_synchronize(&ar->napi);
 	napi_disable(&ar->napi);
+	ath10k_pci_flush(ar);
 
 	spin_lock_irqsave(&ar_pci->ps_lock, flags);
 	WARN_ON(ar_pci->ps_wake_refcount > 0);
-- 
2.20.1


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[PATCH AUTOSEL 4.9 24/64] ath10k: wmi: disable softirq's while calling ieee80211_rx

[Sasha Levin]

From: Erik Stromdahl <erik.stromdahl@gmail.com>

[ Upstream commit 37f62c0d5822f631b786b29a1b1069ab714d1a28 ]

This is done in order not to trig the below warning in
ieee80211_rx_napi:

WARN_ON_ONCE(softirq_count() == 0);

ieee80211_rx_napi requires that softirq's are disabled during
execution.

The High latency bus drivers (SDIO and USB) sometimes call the wmi
ep_rx_complete callback from non softirq context, resulting in a trigger
of the above warning.

Calling ieee80211_rx_ni with softirq's already disabled (e.g., from
softirq context) should be safe as the local_bh_disable and
local_bh_enable functions (called from ieee80211_rx_ni) are fully
reentrant.

Signed-off-by: Erik Stromdahl <erik.stromdahl@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/ath/ath10k/wmi.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath10k/wmi.c b/drivers/net/wireless/ath/ath10k/wmi.c
index bbfe7be214e12..c208fed048554 100644
--- a/drivers/net/wireless/ath/ath10k/wmi.c
+++ b/drivers/net/wireless/ath/ath10k/wmi.c
@@ -2384,7 +2384,8 @@ int ath10k_wmi_event_mgmt_rx(struct ath10k *ar, struct sk_buff *skb)
 		   status->freq, status->band, status->signal,
 		   status->rate_idx);
 
-	ieee80211_rx(ar->hw, skb);
+	ieee80211_rx_ni(ar->hw, skb);
+
 	return 0;
 }
 
-- 
2.20.1


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