ath10k: prevent deinitializing NAPI twice

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 <[email protected]>
Signed-off-by: Kalle Valo <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Wen Gong

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);
 }

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);

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,

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

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

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);