Re: [PATCH ath-next] Revert "wifi: ath12k: add panic handler"

On 6/12/2026 11:23 AM, Yingying Tang wrote:
> This reverts commit 809055628bce824b7fe18331abb65e44d02b0ecf.
> 
> Call trace:
> rcu_note_context_switch+0x4c4/0x508 (P)
> __schedule+0xbc/0x1204
> schedule+0x34/0x110
> schedule_timeout+0x84/0x11c
> __mhi_device_get_sync+0x164/0x228 [mhi]
> mhi_device_get_sync+0x1c/0x3c [mhi]
> ath12k_wifi7_pci_bus_wake_up+0x20/0x2c [ath12k_wifi7]
> ath12k_pci_read32+0x58/0x350 [ath12k]
> ath12k_pci_clear_dbg_registers+0x28/0xb8 [ath12k]
> ath12k_pci_panic_handler+0x20/0x44 [ath12k] ath12k_core_panic_handler+0x28/0x3c [ath12k]
> notifier_call_chain+0x78/0x1c0
> atomic_notifier_call_chain+0x3c/0x5c
> 
> ath12k_core_panic_handler() is invoked via atomic_notifier_call_chain(),
> which runs inside an RCU read-side critical section. The current code calls
> ath12k_pci_sw_reset() synchronously from this context, which eventually
> reaches mhi_device_get_sync() and schedule_timeout(), triggering a voluntary
> context switch within RCU.
> 
> Revert change "wifi: ath12k: add panic handler" to avoid this issue.
> 
> Tested-on: WLAN.HMT.1.1.c7-00108-QCAHMTSWPL_V1.0_V2.0_SILICONZ_UPSTREAM-3

incorrect Tested-on: tag format

> 

Fixes: ?

> Signed-off-by: Yingying Tang <[email protected]>
> ---
>  drivers/net/wireless/ath/ath12k/core.c | 33 +-------------------------
>  drivers/net/wireless/ath/ath12k/core.h |  3 ---
>  drivers/net/wireless/ath/ath12k/hif.h  |  9 -------
>  drivers/net/wireless/ath/ath12k/pci.c  |  8 -------
>  4 files changed, 1 insertion(+), 52 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath12k/core.c b/drivers/net/wireless/ath/ath12k/core.c
> index 1a9866061f82..6705a8a73de1 100644
> --- a/drivers/net/wireless/ath/ath12k/core.c
> +++ b/drivers/net/wireless/ath/ath12k/core.c
> @@ -1793,29 +1793,6 @@ int ath12k_core_pre_init(struct ath12k_base *ab)
>  	return 0;
>  }
>  
> -static int ath12k_core_panic_handler(struct notifier_block *nb,
> -				     unsigned long action, void *data)
> -{
> -	struct ath12k_base *ab = container_of(nb, struct ath12k_base,
> -					      panic_nb);
> -
> -	return ath12k_hif_panic_handler(ab);
> -}
> -
> -static int ath12k_core_panic_notifier_register(struct ath12k_base *ab)
> -{
> -	ab->panic_nb.notifier_call = ath12k_core_panic_handler;
> -
> -	return atomic_notifier_chain_register(&panic_notifier_list,
> -					      &ab->panic_nb);
> -}
> -
> -static void ath12k_core_panic_notifier_unregister(struct ath12k_base *ab)
> -{
> -	atomic_notifier_chain_unregister(&panic_notifier_list,
> -					 &ab->panic_nb);
> -}
> -
>  static inline
>  bool ath12k_core_hw_group_create_ready(struct ath12k_hw_group *ag)
>  {
> @@ -2212,18 +2189,13 @@ int ath12k_core_init(struct ath12k_base *ab)
>  	struct ath12k_hw_group *ag;
>  	int ret;
>  
> -	ret = ath12k_core_panic_notifier_register(ab);
> -	if (ret)
> -		ath12k_warn(ab, "failed to register panic handler: %d\n", ret);
> -
>  	mutex_lock(&ath12k_hw_group_mutex);
>  
>  	ag = ath12k_core_hw_group_assign(ab);
>  	if (!ag) {
>  		mutex_unlock(&ath12k_hw_group_mutex);
>  		ath12k_warn(ab, "unable to get hw group\n");
> -		ret = -ENODEV;
> -		goto err_unregister_notifier;
> +		return -ENODEV;
>  	}
>  
>  	mutex_unlock(&ath12k_hw_group_mutex);
> @@ -2248,8 +2220,6 @@ int ath12k_core_init(struct ath12k_base *ab)
>  
>  err_unassign_hw_group:
>  	ath12k_core_hw_group_unassign(ab);
> -err_unregister_notifier:
> -	ath12k_core_panic_notifier_unregister(ab);
>  
>  	return ret;
>  }
> @@ -2258,7 +2228,6 @@ void ath12k_core_deinit(struct ath12k_base *ab)
>  {
>  	ath12k_core_hw_group_destroy(ab->ag);
>  	ath12k_core_hw_group_unassign(ab);
> -	ath12k_core_panic_notifier_unregister(ab);
>  }
>  
>  void ath12k_core_free(struct ath12k_base *ab)
> diff --git a/drivers/net/wireless/ath/ath12k/core.h b/drivers/net/wireless/ath/ath12k/core.h
> index 4edc8f4e0cb5..a81cb3032145 100644
> --- a/drivers/net/wireless/ath/ath12k/core.h
> +++ b/drivers/net/wireless/ath/ath12k/core.h
> @@ -15,7 +15,6 @@
>  #include <linux/ctype.h>
>  #include <linux/firmware.h>
>  #include <linux/of_reserved_mem.h>
> -#include <linux/panic_notifier.h>
>  #include <linux/average.h>
>  #include <linux/of.h>
>  #include <linux/rhashtable.h>
> @@ -1121,8 +1120,6 @@ struct ath12k_base {
>  
>  #endif /* CONFIG_ACPI */
>  
> -	struct notifier_block panic_nb;
> -
>  	struct ath12k_hw_group *ag;
>  	struct ath12k_wsi_info wsi_info;
>  	enum ath12k_firmware_mode fw_mode;
> diff --git a/drivers/net/wireless/ath/ath12k/hif.h b/drivers/net/wireless/ath/ath12k/hif.h
> index e8840fab6061..42bb00c13ef3 100644
> --- a/drivers/net/wireless/ath/ath12k/hif.h
> +++ b/drivers/net/wireless/ath/ath12k/hif.h
> @@ -30,7 +30,6 @@ struct ath12k_hif_ops {
>  	void (*ce_irq_enable)(struct ath12k_base *ab);
>  	void (*ce_irq_disable)(struct ath12k_base *ab);
>  	void (*get_ce_msi_idx)(struct ath12k_base *ab, u32 ce_id, u32 *msi_idx);
> -	int (*panic_handler)(struct ath12k_base *ab);
>  	void (*coredump_download)(struct ath12k_base *ab);
>  };
>  
> @@ -149,14 +148,6 @@ static inline void ath12k_hif_power_down(struct ath12k_base *ab, bool is_suspend
>  	ab->hif.ops->power_down(ab, is_suspend);
>  }
>  
> -static inline int ath12k_hif_panic_handler(struct ath12k_base *ab)
> -{
> -	if (!ab->hif.ops->panic_handler)
> -		return NOTIFY_DONE;
> -
> -	return ab->hif.ops->panic_handler(ab);
> -}
> -
>  static inline void ath12k_hif_coredump_download(struct ath12k_base *ab)
>  {
>  	if (ab->hif.ops->coredump_download)
> diff --git a/drivers/net/wireless/ath/ath12k/pci.c b/drivers/net/wireless/ath/ath12k/pci.c
> index 375277ca2b89..65a780e74d01 100644
> --- a/drivers/net/wireless/ath/ath12k/pci.c
> +++ b/drivers/net/wireless/ath/ath12k/pci.c
> @@ -1469,13 +1469,6 @@ void ath12k_pci_power_down(struct ath12k_base *ab, bool is_suspend)
>  	ath12k_pci_sw_reset(ab_pci->ab, false);
>  }
>  
> -static int ath12k_pci_panic_handler(struct ath12k_base *ab)
> -{
> -	ath12k_pci_sw_reset(ab, false);
> -
> -	return NOTIFY_OK;
> -}
> -
>  static const struct ath12k_hif_ops ath12k_pci_hif_ops = {
>  	.start = ath12k_pci_start,
>  	.stop = ath12k_pci_stop,
> @@ -1493,7 +1486,6 @@ static const struct ath12k_hif_ops ath12k_pci_hif_ops = {
>  	.ce_irq_enable = ath12k_pci_hif_ce_irq_enable,
>  	.ce_irq_disable = ath12k_pci_hif_ce_irq_disable,
>  	.get_ce_msi_idx = ath12k_pci_get_ce_msi_idx,
> -	.panic_handler = ath12k_pci_panic_handler,
>  #ifdef CONFIG_ATH12K_COREDUMP
>  	.coredump_download = ath12k_pci_coredump_download,
>  #endif