[PATCH 5.11 037/104] ath10k: prevent deinitializing NAPI twice

From: Greg Kroah-Hartman
Date: Fri Mar 05 2021 - 07:26:52 EST


From: Wen Gong <wgong@xxxxxxxxxxxxxx>

[ Upstream commit e2f8b74e58cb1560c1399ba94a470b770e858259 ]

It happened "Kernel panic - not syncing: hung_task: blocked tasks" when
test simulate crash and ifconfig down/rmmod meanwhile.

Test steps:

1.Test commands, either can reproduce the hang for PCIe, SDIO and SNOC.
echo soft > /sys/kernel/debug/ieee80211/phy0/ath10k/simulate_fw_crash;sleep 0.05;ifconfig wlan0 down
echo soft > /sys/kernel/debug/ieee80211/phy0/ath10k/simulate_fw_crash;rmmod ath10k_sdio
echo hw-restart > /sys/kernel/debug/ieee80211/phy0/ath10k/simulate_fw_crash;rmmod ath10k_pci

2. dmesg:
[ 5622.548630] ath10k_sdio mmc1:0001:1: simulating soft firmware crash
[ 5622.655995] ieee80211 phy0: Hardware restart was requested
[ 5776.355164] INFO: task shill:1572 blocked for more than 122 seconds.
[ 5776.355687] INFO: task kworker/1:2:24437 blocked for more than 122 seconds.
[ 5776.359812] Kernel panic - not syncing: hung_task: blocked tasks
[ 5776.359836] CPU: 1 PID: 55 Comm: khungtaskd Tainted: G W 4.19.86 #137
[ 5776.359846] Hardware name: MediaTek krane sku176 board (DT)
[ 5776.359855] Call trace:
[ 5776.359868] dump_backtrace+0x0/0x170
[ 5776.359881] show_stack+0x20/0x2c
[ 5776.359896] dump_stack+0xd4/0x10c
[ 5776.359916] panic+0x12c/0x29c
[ 5776.359937] hung_task_panic+0x0/0x50
[ 5776.359953] kthread+0x120/0x130
[ 5776.359965] ret_from_fork+0x10/0x18
[ 5776.359986] SMP: stopping secondary CPUs
[ 5776.360012] Kernel Offset: 0x141ea00000 from 0xffffff8008000000
[ 5776.360026] CPU features: 0x0,2188200c
[ 5776.360035] Memory Limit: none

command "ifconfig wlan0 down" or "rmmod ath10k_sdio" will be blocked
callstack of ifconfig:
[<0>] __switch_to+0x120/0x13c
[<0>] msleep+0x28/0x38
[<0>] ath10k_sdio_hif_stop+0x24c/0x294 [ath10k_sdio]
[<0>] ath10k_core_stop+0x50/0x78 [ath10k_core]
[<0>] ath10k_halt+0x120/0x178 [ath10k_core]
[<0>] ath10k_stop+0x4c/0x8c [ath10k_core]
[<0>] drv_stop+0xe0/0x1e4 [mac80211]
[<0>] ieee80211_stop_device+0x48/0x54 [mac80211]
[<0>] ieee80211_do_stop+0x678/0x6f8 [mac80211]
[<0>] ieee80211_stop+0x20/0x30 [mac80211]
[<0>] __dev_close_many+0xb8/0x11c
[<0>] __dev_change_flags+0xe0/0x1d0
[<0>] dev_change_flags+0x30/0x6c
[<0>] devinet_ioctl+0x370/0x564
[<0>] inet_ioctl+0xdc/0x304
[<0>] sock_do_ioctl+0x50/0x288
[<0>] compat_sock_ioctl+0x1b4/0x1aac
[<0>] __se_compat_sys_ioctl+0x100/0x26fc
[<0>] __arm64_compat_sys_ioctl+0x20/0x2c
[<0>] el0_svc_common+0xa4/0x154
[<0>] el0_svc_compat_handler+0x2c/0x38
[<0>] el0_svc_compat+0x8/0x18
[<0>] 0xffffffffffffffff

callstack of rmmod:
[<0>] __switch_to+0x120/0x13c
[<0>] msleep+0x28/0x38
[<0>] ath10k_sdio_hif_stop+0x294/0x31c [ath10k_sdio]
[<0>] ath10k_core_stop+0x50/0x78 [ath10k_core]
[<0>] ath10k_halt+0x120/0x178 [ath10k_core]
[<0>] ath10k_stop+0x4c/0x8c [ath10k_core]
[<0>] drv_stop+0xe0/0x1e4 [mac80211]
[<0>] ieee80211_stop_device+0x48/0x54 [mac80211]
[<0>] ieee80211_do_stop+0x678/0x6f8 [mac80211]
[<0>] ieee80211_stop+0x20/0x30 [mac80211]
[<0>] __dev_close_many+0xb8/0x11c
[<0>] dev_close_many+0x70/0x100
[<0>] dev_close+0x4c/0x80
[<0>] cfg80211_shutdown_all_interfaces+0x50/0xcc [cfg80211]
[<0>] ieee80211_remove_interfaces+0x58/0x1a0 [mac80211]
[<0>] ieee80211_unregister_hw+0x40/0x100 [mac80211]
[<0>] ath10k_mac_unregister+0x1c/0x44 [ath10k_core]
[<0>] ath10k_core_unregister+0x38/0x7c [ath10k_core]
[<0>] ath10k_sdio_remove+0x8c/0xd0 [ath10k_sdio]
[<0>] sdio_bus_remove+0x48/0x108
[<0>] device_release_driver_internal+0x138/0x1ec
[<0>] driver_detach+0x6c/0xa8
[<0>] bus_remove_driver+0x78/0xa8
[<0>] driver_unregister+0x30/0x50
[<0>] sdio_unregister_driver+0x28/0x34
[<0>] cleanup_module+0x14/0x6bc [ath10k_sdio]
[<0>] __arm64_sys_delete_module+0x1e0/0x22c
[<0>] el0_svc_common+0xa4/0x154
[<0>] el0_svc_compat_handler+0x2c/0x38
[<0>] el0_svc_compat+0x8/0x18
[<0>] 0xffffffffffffffff

SNOC:
[ 647.156863] Call trace:
[ 647.162166] [<ffffff80080855a4>] __switch_to+0x120/0x13c
[ 647.164512] [<ffffff800899d8b8>] __schedule+0x5ec/0x798
[ 647.170062] [<ffffff800899dad8>] schedule+0x74/0x94
[ 647.175050] [<ffffff80089a0848>] schedule_timeout+0x314/0x42c
[ 647.179874] [<ffffff80089a0a14>] schedule_timeout_uninterruptible+0x34/0x40
[ 647.185780] [<ffffff80082a494>] msleep+0x28/0x38
[ 647.192546] [<ffffff800117ec4c>] ath10k_snoc_hif_stop+0x4c/0x1e0 [ath10k_snoc]
[ 647.197439] [<ffffff80010dfbd8>] ath10k_core_stop+0x50/0x7c [ath10k_core]
[ 647.204652] [<ffffff80010c8f48>] ath10k_halt+0x114/0x16c [ath10k_core]
[ 647.211420] [<ffffff80010cad68>] ath10k_stop+0x4c/0x88 [ath10k_core]
[ 647.217865] [<ffffff8000fdbf54>] drv_stop+0x110/0x244 [mac80211]
[ 647.224367] [<ffffff80010147ac>] ieee80211_stop_device+0x48/0x54 [mac80211]
[ 647.230359] [<ffffff8000ff3eec>] ieee80211_do_stop+0x6a4/0x73c [mac80211]
[ 647.237033] [<ffffff8000ff4500>] ieee80211_stop+0x20/0x30 [mac80211]
[ 647.243942] [<ffffff80087e39b8>] __dev_close_many+0xa0/0xfc
[ 647.250435] [<ffffff80087e3888>] dev_close_many+0x70/0x100
[ 647.255651] [<ffffff80087e3a60>] dev_close+0x4c/0x80
[ 647.261244] [<ffffff8000f1ba54>] cfg80211_shutdown_all_interfaces+0x44/0xcc [cfg80211]
[ 647.266383] [<ffffff8000ff3fdc>] ieee80211_remove_interfaces+0x58/0x1b4 [mac80211]
[ 647.274128] [<ffffff8000fda540>] ieee80211_unregister_hw+0x50/0x120 [mac80211]
[ 647.281659] [<ffffff80010ca314>] ath10k_mac_unregister+0x1c/0x44 [ath10k_core]
[ 647.288839] [<ffffff80010dfc94>] ath10k_core_unregister+0x48/0x90 [ath10k_core]
[ 647.296027] [<ffffff800117e598>] ath10k_snoc_remove+0x5c/0x150 [ath10k_snoc]
[ 647.303229] [<ffffff80085625fc>] platform_drv_remove+0x28/0x50
[ 647.310517] [<ffffff80085601a4>] device_release_driver_internal+0x114/0x1b8
[ 647.316257] [<ffffff80085602e4>] driver_detach+0x6c/0xa8
[ 647.323021] [<ffffff800855e5b8>] bus_remove_driver+0x78/0xa8
[ 647.328571] [<ffffff800856107c>] driver_unregister+0x30/0x50
[ 647.334213] [<ffffff8008562674>] platform_driver_unregister+0x1c/0x28
[ 647.339876] [<ffffff800117fefc>] cleanup_module+0x1c/0x120 [ath10k_snoc]
[ 647.346196] [<ffffff8008143ab8>] SyS_delete_module+0x1dc/0x22c

PCIe:
[ 615.392770] rmmod D 0 3523 3458 0x00000080
[ 615.392777] Call Trace:
[ 615.392784] __schedule+0x617/0x7d3
[ 615.392791] ? __mod_timer+0x263/0x35c
[ 615.392797] schedule+0x62/0x72
[ 615.392803] schedule_timeout+0x8d/0xf3
[ 615.392809] ? run_local_timers+0x6b/0x6b
[ 615.392814] msleep+0x1b/0x22
[ 615.392824] ath10k_pci_hif_stop+0x68/0xd6 [ath10k_pci]
[ 615.392844] ath10k_core_stop+0x44/0x67 [ath10k_core]
[ 615.392859] ath10k_halt+0x102/0x153 [ath10k_core]
[ 615.392873] ath10k_stop+0x38/0x75 [ath10k_core]
[ 615.392893] drv_stop+0x9a/0x13c [mac80211]
[ 615.392915] ieee80211_do_stop+0x772/0x7cd [mac80211]
[ 615.392937] ieee80211_stop+0x1a/0x1e [mac80211]
[ 615.392945] __dev_close_many+0x9e/0xf0
[ 615.392952] dev_close_many+0x62/0xe8
[ 615.392958] dev_close+0x54/0x7d
[ 615.392975] cfg80211_shutdown_all_interfaces+0x6e/0xa5 [cfg80211]
[ 615.393021] ieee80211_remove_interfaces+0x52/0x1aa [mac80211]
[ 615.393049] ieee80211_unregister_hw+0x54/0x136 [mac80211]
[ 615.393068] ath10k_mac_unregister+0x19/0x4a [ath10k_core]
[ 615.393091] ath10k_core_unregister+0x39/0x7e [ath10k_core]
[ 615.393104] ath10k_pci_remove+0x3d/0x7f [ath10k_pci]
[ 615.393117] pci_device_remove+0x41/0xa6
[ 615.393129] device_release_driver_internal+0x123/0x1ec
[ 615.393140] driver_detach+0x60/0x90
[ 615.393152] bus_remove_driver+0x72/0x9f
[ 615.393164] pci_unregister_driver+0x1e/0x87
[ 615.393177] SyS_delete_module+0x1d7/0x277
[ 615.393188] do_syscall_64+0x6b/0xf7
[ 615.393199] entry_SYSCALL_64_after_hwframe+0x41/0xa6

The test command run simulate_fw_crash firstly and it call into
ath10k_sdio_hif_stop from ath10k_core_restart, then napi_disable
is called and bit NAPI_STATE_SCHED is set. After that, function
ath10k_sdio_hif_stop is called again from ath10k_stop by command
"ifconfig wlan0 down" or "rmmod ath10k_sdio", then command blocked.

It is blocked by napi_synchronize, napi_disable will set bit with
NAPI_STATE_SCHED, and then napi_synchronize will enter dead loop
becuase bit NAPI_STATE_SCHED is set by napi_disable.

function of napi_synchronize
static inline void napi_synchronize(const struct napi_struct *n)
{
if (IS_ENABLED(CONFIG_SMP))
while (test_bit(NAPI_STATE_SCHED, &n->state))
msleep(1);
else
barrier();
}

function of napi_disable
void napi_disable(struct napi_struct *n)
{
might_sleep();
set_bit(NAPI_STATE_DISABLE, &n->state);

while (test_and_set_bit(NAPI_STATE_SCHED, &n->state))
msleep(1);
while (test_and_set_bit(NAPI_STATE_NPSVC, &n->state))
msleep(1);

hrtimer_cancel(&n->timer);

clear_bit(NAPI_STATE_DISABLE, &n->state);
}

Add flag for it avoid the hang and crash.

Tested-on: QCA6174 hw3.2 SDIO WLAN.RMH.4.4.1-00049
Tested-on: QCA6174 hw3.2 PCI WLAN.RM.4.4.1-00110-QCARMSWP-1
Tested-on: WCN3990 hw1.0 SNOC hw1.0 WLAN.HL.3.1-01307.1-QCAHLSWMTPL-2

Signed-off-by: Wen Gong <wgong@xxxxxxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/1598617348-2325-1-git-send-email-wgong@xxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/wireless/ath/ath10k/ahb.c | 5 ++---
drivers/net/wireless/ath/ath10k/core.c | 25 +++++++++++++++++++++++++
drivers/net/wireless/ath/ath10k/core.h | 5 +++++
drivers/net/wireless/ath/ath10k/pci.c | 7 ++++---
drivers/net/wireless/ath/ath10k/sdio.c | 5 ++---
drivers/net/wireless/ath/ath10k/snoc.c | 6 +++---
6 files changed, 41 insertions(+), 12 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/ahb.c b/drivers/net/wireless/ath/ath10k/ahb.c
index 05a61975c83f..869524852fba 100644
--- a/drivers/net/wireless/ath/ath10k/ahb.c
+++ b/drivers/net/wireless/ath/ath10k/ahb.c
@@ -626,7 +626,7 @@ static int ath10k_ahb_hif_start(struct ath10k *ar)
{
ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot ahb hif start\n");

- napi_enable(&ar->napi);
+ ath10k_core_napi_enable(ar);
ath10k_ce_enable_interrupts(ar);
ath10k_pci_enable_legacy_irq(ar);

@@ -644,8 +644,7 @@ static void ath10k_ahb_hif_stop(struct ath10k *ar)
ath10k_ahb_irq_disable(ar);
synchronize_irq(ar_ahb->irq);

- napi_synchronize(&ar->napi);
- napi_disable(&ar->napi);
+ ath10k_core_napi_sync_disable(ar);

ath10k_pci_flush(ar);
}
diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
index eeb6ff6aa2e1..a419ec7130f9 100644
--- a/drivers/net/wireless/ath/ath10k/core.c
+++ b/drivers/net/wireless/ath/ath10k/core.c
@@ -2305,6 +2305,31 @@ void ath10k_core_start_recovery(struct ath10k *ar)
}
EXPORT_SYMBOL(ath10k_core_start_recovery);

+void ath10k_core_napi_enable(struct ath10k *ar)
+{
+ lockdep_assert_held(&ar->conf_mutex);
+
+ if (test_bit(ATH10K_FLAG_NAPI_ENABLED, &ar->dev_flags))
+ return;
+
+ napi_enable(&ar->napi);
+ set_bit(ATH10K_FLAG_NAPI_ENABLED, &ar->dev_flags);
+}
+EXPORT_SYMBOL(ath10k_core_napi_enable);
+
+void ath10k_core_napi_sync_disable(struct ath10k *ar)
+{
+ lockdep_assert_held(&ar->conf_mutex);
+
+ if (!test_bit(ATH10K_FLAG_NAPI_ENABLED, &ar->dev_flags))
+ return;
+
+ napi_synchronize(&ar->napi);
+ napi_disable(&ar->napi);
+ clear_bit(ATH10K_FLAG_NAPI_ENABLED, &ar->dev_flags);
+}
+EXPORT_SYMBOL(ath10k_core_napi_sync_disable);
+
static void ath10k_core_restart(struct work_struct *work)
{
struct ath10k *ar = container_of(work, struct ath10k, restart_work);
diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h
index 51f7e960e297..f4be6bfb2539 100644
--- a/drivers/net/wireless/ath/ath10k/core.h
+++ b/drivers/net/wireless/ath/ath10k/core.h
@@ -868,6 +868,9 @@ enum ath10k_dev_flags {

/* Indicates that ath10k device is during recovery process and not complete */
ATH10K_FLAG_RESTARTING,
+
+ /* protected by conf_mutex */
+ ATH10K_FLAG_NAPI_ENABLED,
};

enum ath10k_cal_mode {
@@ -1308,6 +1311,8 @@ static inline bool ath10k_peer_stats_enabled(struct ath10k *ar)

extern unsigned long ath10k_coredump_mask;

+void ath10k_core_napi_sync_disable(struct ath10k *ar);
+void ath10k_core_napi_enable(struct ath10k *ar);
struct ath10k *ath10k_core_create(size_t priv_size, struct device *dev,
enum ath10k_bus bus,
enum ath10k_hw_rev hw_rev,
diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index 2328df09875c..e7fde635e0ee 100644
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/drivers/net/wireless/ath/ath10k/pci.c
@@ -1958,7 +1958,7 @@ static int ath10k_pci_hif_start(struct ath10k *ar)

ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot hif start\n");

- napi_enable(&ar->napi);
+ ath10k_core_napi_enable(ar);

ath10k_pci_irq_enable(ar);
ath10k_pci_rx_post(ar);
@@ -2075,8 +2075,9 @@ static void ath10k_pci_hif_stop(struct ath10k *ar)

ath10k_pci_irq_disable(ar);
ath10k_pci_irq_sync(ar);
- napi_synchronize(&ar->napi);
- napi_disable(&ar->napi);
+
+ ath10k_core_napi_sync_disable(ar);
+
cancel_work_sync(&ar_pci->dump_work);

/* Most likely the device has HTT Rx ring configured. The only way to
diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c
index c415090d1f37..b746052737e0 100644
--- a/drivers/net/wireless/ath/ath10k/sdio.c
+++ b/drivers/net/wireless/ath/ath10k/sdio.c
@@ -1859,7 +1859,7 @@ static int ath10k_sdio_hif_start(struct ath10k *ar)
struct ath10k_sdio *ar_sdio = ath10k_sdio_priv(ar);
int ret;

- napi_enable(&ar->napi);
+ ath10k_core_napi_enable(ar);

/* Sleep 20 ms before HIF interrupts are disabled.
* This will give target plenty of time to process the BMI done
@@ -1992,8 +1992,7 @@ static void ath10k_sdio_hif_stop(struct ath10k *ar)

spin_unlock_bh(&ar_sdio->wr_async_lock);

- napi_synchronize(&ar->napi);
- napi_disable(&ar->napi);
+ ath10k_core_napi_sync_disable(ar);
}

#ifdef CONFIG_PM
diff --git a/drivers/net/wireless/ath/ath10k/snoc.c b/drivers/net/wireless/ath/ath10k/snoc.c
index 1c3307e3b108..af7ecef6bcde 100644
--- a/drivers/net/wireless/ath/ath10k/snoc.c
+++ b/drivers/net/wireless/ath/ath10k/snoc.c
@@ -915,8 +915,7 @@ static void ath10k_snoc_hif_stop(struct ath10k *ar)
if (!test_bit(ATH10K_FLAG_CRASH_FLUSH, &ar->dev_flags))
ath10k_snoc_irq_disable(ar);

- napi_synchronize(&ar->napi);
- napi_disable(&ar->napi);
+ ath10k_core_napi_sync_disable(ar);
ath10k_snoc_buffer_cleanup(ar);
ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot hif stop\n");
}
@@ -926,7 +925,8 @@ static int ath10k_snoc_hif_start(struct ath10k *ar)
struct ath10k_snoc *ar_snoc = ath10k_snoc_priv(ar);

bitmap_clear(ar_snoc->pending_ce_irqs, 0, CE_COUNT_MAX);
- napi_enable(&ar->napi);
+
+ ath10k_core_napi_enable(ar);
ath10k_snoc_irq_enable(ar);
ath10k_snoc_rx_post(ar);

--
2.30.1