Re: [PATCH V1] accel/amdxdna: Fix dead lock for suspend and resume

[Mario Limonciello <mario.limonciello@amd.com>]

On 2/10/26 1:16 PM, Lizhi Hou wrote:
> When an application issues a query IOCTL while auto suspend is running,
> a deadlock can occur. The query path holds dev_lock and then calls
> pm_runtime_resume_and_get(), which waits for the ongoing suspend to
> complete. Meanwhile, the suspend callback attempts to acquire dev_lock
> and blocks, resulting in a deadlock.
> 
> Fix this by releasing dev_lock before calling pm_runtime_resume_and_get()
> and reacquiring it after the call completes. Also acquire dev_lock in the
> resume callback to keep the locking consistent.
> 
> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
No Fixes tag?

> ---
>   drivers/accel/amdxdna/aie2_ctx.c    |  4 ++--
>   drivers/accel/amdxdna/aie2_pci.c    |  7 +++----
>   drivers/accel/amdxdna/aie2_pm.c     |  2 +-
>   drivers/accel/amdxdna/amdxdna_ctx.c | 19 +++++++------------
>   drivers/accel/amdxdna/amdxdna_pm.c  |  2 ++
>   drivers/accel/amdxdna/amdxdna_pm.h  | 11 +++++++++++
>   6 files changed, 26 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/accel/amdxdna/aie2_ctx.c b/drivers/accel/amdxdna/aie2_ctx.c
> index 37d05f2e986f..58e146172b61 100644
> --- a/drivers/accel/amdxdna/aie2_ctx.c
> +++ b/drivers/accel/amdxdna/aie2_ctx.c
> @@ -629,7 +629,7 @@ int aie2_hwctx_init(struct amdxdna_hwctx *hwctx)
>   		goto free_entity;
>   	}
>   
> -	ret = amdxdna_pm_resume_get(xdna);
> +	ret = amdxdna_pm_resume_get_locked(xdna);
>   	if (ret)
>   		goto free_col_list;
>   
> @@ -760,7 +760,7 @@ static int aie2_hwctx_cu_config(struct amdxdna_hwctx *hwctx, void *buf, u32 size
>   	if (!hwctx->cus)
>   		return -ENOMEM;
>   
> -	ret = amdxdna_pm_resume_get(xdna);
> +	ret = amdxdna_pm_resume_get_locked(xdna);
>   	if (ret)
>   		goto free_cus;
>   
> diff --git a/drivers/accel/amdxdna/aie2_pci.c b/drivers/accel/amdxdna/aie2_pci.c
> index f70ccf0f3c01..5b326e4610e6 100644
> --- a/drivers/accel/amdxdna/aie2_pci.c
> +++ b/drivers/accel/amdxdna/aie2_pci.c
> @@ -451,7 +451,6 @@ static int aie2_hw_suspend(struct amdxdna_dev *xdna)
>   {
>   	struct amdxdna_client *client;
>   
> -	guard(mutex)(&xdna->dev_lock);
>   	list_for_each_entry(client, &xdna->client_list, node)
>   		aie2_hwctx_suspend(client);
>   
> @@ -951,7 +950,7 @@ static int aie2_get_info(struct amdxdna_client *client, struct amdxdna_drm_get_i
>   	if (!drm_dev_enter(&xdna->ddev, &idx))
>   		return -ENODEV;
>   
> -	ret = amdxdna_pm_resume_get(xdna);
> +	ret = amdxdna_pm_resume_get_locked(xdna);
>   	if (ret)
>   		goto dev_exit;
>   
> @@ -1044,7 +1043,7 @@ static int aie2_get_array(struct amdxdna_client *client,
>   	if (!drm_dev_enter(&xdna->ddev, &idx))
>   		return -ENODEV;
>   
> -	ret = amdxdna_pm_resume_get(xdna);
> +	ret = amdxdna_pm_resume_get_locked(xdna);
>   	if (ret)
>   		goto dev_exit;
>   
> @@ -1134,7 +1133,7 @@ static int aie2_set_state(struct amdxdna_client *client,
>   	if (!drm_dev_enter(&xdna->ddev, &idx))
>   		return -ENODEV;
>   
> -	ret = amdxdna_pm_resume_get(xdna);
> +	ret = amdxdna_pm_resume_get_locked(xdna);
>   	if (ret)
>   		goto dev_exit;
>   
> diff --git a/drivers/accel/amdxdna/aie2_pm.c b/drivers/accel/amdxdna/aie2_pm.c
> index 579b8be13b18..29bd4403a94d 100644
> --- a/drivers/accel/amdxdna/aie2_pm.c
> +++ b/drivers/accel/amdxdna/aie2_pm.c
> @@ -31,7 +31,7 @@ int aie2_pm_set_dpm(struct amdxdna_dev_hdl *ndev, u32 dpm_level)
>   {
>   	int ret;
>   
> -	ret = amdxdna_pm_resume_get(ndev->xdna);
> +	ret = amdxdna_pm_resume_get_locked(ndev->xdna);
>   	if (ret)
>   		return ret;
>   
> diff --git a/drivers/accel/amdxdna/amdxdna_ctx.c b/drivers/accel/amdxdna/amdxdna_ctx.c
> index d17aef89a0ad..db3aa26fb55f 100644
> --- a/drivers/accel/amdxdna/amdxdna_ctx.c
> +++ b/drivers/accel/amdxdna/amdxdna_ctx.c
> @@ -266,9 +266,9 @@ int amdxdna_drm_config_hwctx_ioctl(struct drm_device *dev, void *data, struct dr
>   	struct amdxdna_drm_config_hwctx *args = data;
>   	struct amdxdna_dev *xdna = to_xdna_dev(dev);
>   	struct amdxdna_hwctx *hwctx;
> -	int ret, idx;
>   	u32 buf_size;
>   	void *buf;
> +	int ret;
>   	u64 val;
>   
>   	if (XDNA_MBZ_DBG(xdna, &args->pad, sizeof(args->pad)))
> @@ -310,20 +310,17 @@ int amdxdna_drm_config_hwctx_ioctl(struct drm_device *dev, void *data, struct dr
>   		return -EINVAL;
>   	}
>   
> -	mutex_lock(&xdna->dev_lock);
> -	idx = srcu_read_lock(&client->hwctx_srcu);
> +	guard(mutex)(&xdna->dev_lock);
>   	hwctx = xa_load(&client->hwctx_xa, args->handle);
>   	if (!hwctx) {
>   		XDNA_DBG(xdna, "PID %d failed to get hwctx %d", client->pid, args->handle);
>   		ret = -EINVAL;
> -		goto unlock_srcu;
> +		goto free_buf;
>   	}
>   
>   	ret = xdna->dev_info->ops->hwctx_config(hwctx, args->param_type, val, buf, buf_size);
>   
> -unlock_srcu:
> -	srcu_read_unlock(&client->hwctx_srcu, idx);
> -	mutex_unlock(&xdna->dev_lock);
> +free_buf:
>   	kfree(buf);
>   	return ret;
>   }
> @@ -334,7 +331,7 @@ int amdxdna_hwctx_sync_debug_bo(struct amdxdna_client *client, u32 debug_bo_hdl)
>   	struct amdxdna_hwctx *hwctx;
>   	struct amdxdna_gem_obj *abo;
>   	struct drm_gem_object *gobj;
> -	int ret, idx;
> +	int ret;
>   
>   	if (!xdna->dev_info->ops->hwctx_sync_debug_bo)
>   		return -EOPNOTSUPP;
> @@ -345,17 +342,15 @@ int amdxdna_hwctx_sync_debug_bo(struct amdxdna_client *client, u32 debug_bo_hdl)
>   
>   	abo = to_xdna_obj(gobj);
>   	guard(mutex)(&xdna->dev_lock);
> -	idx = srcu_read_lock(&client->hwctx_srcu);
>   	hwctx = xa_load(&client->hwctx_xa, abo->assigned_hwctx);
>   	if (!hwctx) {
>   		ret = -EINVAL;
> -		goto unlock_srcu;
> +		goto put_obj;
>   	}
>   
>   	ret = xdna->dev_info->ops->hwctx_sync_debug_bo(hwctx, debug_bo_hdl);
>   
> -unlock_srcu:
> -	srcu_read_unlock(&client->hwctx_srcu, idx);
> +put_obj:
>   	drm_gem_object_put(gobj);
>   	return ret;
>   }
> diff --git a/drivers/accel/amdxdna/amdxdna_pm.c b/drivers/accel/amdxdna/amdxdna_pm.c
> index d024d480521c..b1fafddd7ad5 100644
> --- a/drivers/accel/amdxdna/amdxdna_pm.c
> +++ b/drivers/accel/amdxdna/amdxdna_pm.c
> @@ -16,6 +16,7 @@ int amdxdna_pm_suspend(struct device *dev)
>   	struct amdxdna_dev *xdna = to_xdna_dev(dev_get_drvdata(dev));
>   	int ret = -EOPNOTSUPP;
>   
> +	guard(mutex)(&xdna->dev_lock);
>   	if (xdna->dev_info->ops->suspend)
>   		ret = xdna->dev_info->ops->suspend(xdna);
>   
> @@ -28,6 +29,7 @@ int amdxdna_pm_resume(struct device *dev)
>   	struct amdxdna_dev *xdna = to_xdna_dev(dev_get_drvdata(dev));
>   	int ret = -EOPNOTSUPP;
>   
> +	guard(mutex)(&xdna->dev_lock);
>   	if (xdna->dev_info->ops->resume)
>   		ret = xdna->dev_info->ops->resume(xdna);
>   
> diff --git a/drivers/accel/amdxdna/amdxdna_pm.h b/drivers/accel/amdxdna/amdxdna_pm.h
> index 77b2d6e45570..3d26b973e0e3 100644
> --- a/drivers/accel/amdxdna/amdxdna_pm.h
> +++ b/drivers/accel/amdxdna/amdxdna_pm.h
> @@ -15,4 +15,15 @@ void amdxdna_pm_suspend_put(struct amdxdna_dev *xdna);
>   void amdxdna_pm_init(struct amdxdna_dev *xdna);
>   void amdxdna_pm_fini(struct amdxdna_dev *xdna);
>   
> +static inline int amdxdna_pm_resume_get_locked(struct amdxdna_dev *xdna)
> +{
> +	int ret;
> +
> +	mutex_unlock(&xdna->dev_lock);
> +	ret = amdxdna_pm_resume_get(xdna);
> +	mutex_lock(&xdna->dev_lock);
> +
> +	return ret;
> +}
> +
>   #endif /* _AMDXDNA_PM_H_ */