Re: [PATCH v2,1/2] media: mediatek: vcodec: checking decoder ack message parameter

[Nicolas Dufresne]

Hi Yunfei,

Le samedi 22 juillet 2023 à 15:46 +0800, Yunfei Dong a écrit :
> Need to checking all parameters of msg data are valid or not,
> in case of access null pointer or unreasonable value leading
> to kernel reboot.

May I suggest an alternative commit message ? It would look like:
   
   
   media: mediatek: vcodec: Fix possible invalid memory access
   
   Validate that the context pointer and the vpu instance within this
   context is valid. <please add why it may occur here>


I cannot really provide a full message here, but my understanding is that it is
normal behaviour for the IRQ handler to be called after the context or the VPU
instance has been released ? It is unlikely a great programming pattern though,
can't you remove the handler on time instead ?

Nicolas

> 
> Signed-off-by: Yunfei Dong <yunfei.dong@xxxxxxxxxxxx>
> Reviewed-by: Nicolas Dufresne <nicolas.dufresne@xxxxxxxxxxxxx>
> ---
>  .../vcodec/decoder/mtk_vcodec_dec_drv.h       |  2 +
>  .../mediatek/vcodec/decoder/vdec_vpu_if.c     | 77 ++++++++++++-------
>  2 files changed, 52 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.h b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.h
> index 6c318de25a55..7e36b2c69b7d 100644
> --- a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.h
> +++ b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.h
> @@ -161,6 +161,7 @@ struct mtk_vcodec_dec_pdata {
>   * @hw_id: hardware index used to identify different hardware.
>   *
>   * @msg_queue: msg queue used to store lat buffer information.
> + * @vpu_inst: vpu instance pointer.
>   *
>   * @is_10bit_bitstream: set to true if it's 10bit bitstream
>   */
> @@ -205,6 +206,7 @@ struct mtk_vcodec_dec_ctx {
>  	int hw_id;
>  
>  	struct vdec_msg_queue msg_queue;
> +	void *vpu_inst;
>  
>  	bool is_10bit_bitstream;
>  };
> diff --git a/drivers/media/platform/mediatek/vcodec/decoder/vdec_vpu_if.c b/drivers/media/platform/mediatek/vcodec/decoder/vdec_vpu_if.c
> index 82c3dc8c4127..23cfe5c6c90b 100644
> --- a/drivers/media/platform/mediatek/vcodec/decoder/vdec_vpu_if.c
> +++ b/drivers/media/platform/mediatek/vcodec/decoder/vdec_vpu_if.c
> @@ -72,6 +72,21 @@ static void handle_get_param_msg_ack(const struct vdec_vpu_ipi_get_param_ack *ms
>  	}
>  }
>  
> +static bool vpu_dec_check_ap_inst(struct mtk_vcodec_dec_dev *dec_dev, struct vdec_vpu_inst *vpu)
> +{
> +	struct mtk_vcodec_dec_ctx *ctx;
> +	int ret = false;
> +
> +	list_for_each_entry(ctx, &dec_dev->ctx_list, list) {
> +		if (!IS_ERR_OR_NULL(ctx) && ctx->vpu_inst == vpu) {
> +			ret = true;
> +			break;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
>  /*
>   * vpu_dec_ipi_handler - Handler for VPU ipi message.
>   *
> @@ -84,44 +99,51 @@ static void handle_get_param_msg_ack(const struct vdec_vpu_ipi_get_param_ack *ms
>   */
>  static void vpu_dec_ipi_handler(void *data, unsigned int len, void *priv)
>  {
> +	struct mtk_vcodec_dec_dev *dec_dev;
>  	const struct vdec_vpu_ipi_ack *msg = data;
> -	struct vdec_vpu_inst *vpu = (struct vdec_vpu_inst *)
> -					(unsigned long)msg->ap_inst_addr;
> +	struct vdec_vpu_inst *vpu;
>  
> -	if (!vpu) {
> +	dec_dev = (struct mtk_vcodec_dec_dev *)priv;
> +	vpu = (struct vdec_vpu_inst *)(unsigned long)msg->ap_inst_addr;
> +	if (!priv || !vpu) {
>  		mtk_v4l2_vdec_err(vpu->ctx, "ap_inst_addr is NULL, did the SCP hang or crash?");
>  		return;
>  	}
>  
> -	mtk_vdec_debug(vpu->ctx, "+ id=%X", msg->msg_id);
> +	if (!vpu_dec_check_ap_inst(dec_dev, vpu) || msg->msg_id < VPU_IPIMSG_DEC_INIT_ACK ||
> +	    msg->msg_id > VPU_IPIMSG_DEC_GET_PARAM_ACK) {
> +		mtk_v4l2_vdec_err(vpu->ctx, "vdec msg id not correctly => 0x%x", msg->msg_id);
> +		vpu->failure = -EINVAL;
> +		goto error;
> +	}
>  
>  	vpu->failure = msg->status;
> -	vpu->signaled = 1;
> +	if (msg->status != 0)
> +		goto error;
>  
> -	if (msg->status == 0) {
> -		switch (msg->msg_id) {
> -		case VPU_IPIMSG_DEC_INIT_ACK:
> -			handle_init_ack_msg(data);
> -			break;
> +	switch (msg->msg_id) {
> +	case VPU_IPIMSG_DEC_INIT_ACK:
> +		handle_init_ack_msg(data);
> +		break;
>  
> -		case VPU_IPIMSG_DEC_START_ACK:
> -		case VPU_IPIMSG_DEC_END_ACK:
> -		case VPU_IPIMSG_DEC_DEINIT_ACK:
> -		case VPU_IPIMSG_DEC_RESET_ACK:
> -		case VPU_IPIMSG_DEC_CORE_ACK:
> -		case VPU_IPIMSG_DEC_CORE_END_ACK:
> -			break;
> +	case VPU_IPIMSG_DEC_START_ACK:
> +	case VPU_IPIMSG_DEC_END_ACK:
> +	case VPU_IPIMSG_DEC_DEINIT_ACK:
> +	case VPU_IPIMSG_DEC_RESET_ACK:
> +	case VPU_IPIMSG_DEC_CORE_ACK:
> +	case VPU_IPIMSG_DEC_CORE_END_ACK:
> +		break;
>  
> -		case VPU_IPIMSG_DEC_GET_PARAM_ACK:
> -			handle_get_param_msg_ack(data);
> -			break;
> -		default:
> -			mtk_vdec_err(vpu->ctx, "invalid msg=%X", msg->msg_id);
> -			break;
> -		}
> +	case VPU_IPIMSG_DEC_GET_PARAM_ACK:
> +		handle_get_param_msg_ack(data);
> +		break;
> +	default:
> +		mtk_vdec_err(vpu->ctx, "invalid msg=%X", msg->msg_id);
> +		break;
>  	}
>  
> -	mtk_vdec_debug(vpu->ctx, "- id=%X", msg->msg_id);
> +error:
> +	vpu->signaled = 1;
>  }
>  
>  static int vcodec_vpu_send_msg(struct vdec_vpu_inst *vpu, void *msg, int len)
> @@ -182,9 +204,10 @@ int vpu_dec_init(struct vdec_vpu_inst *vpu)
>  
>  	init_waitqueue_head(&vpu->wq);
>  	vpu->handler = vpu_dec_ipi_handler;
> +	vpu->ctx->vpu_inst = vpu;
>  
>  	err = mtk_vcodec_fw_ipi_register(vpu->ctx->dev->fw_handler, vpu->id,
> -					 vpu->handler, "vdec", NULL);
> +					 vpu->handler, "vdec", vpu->ctx->dev);
>  	if (err) {
>  		mtk_vdec_err(vpu->ctx, "vpu_ipi_register fail status=%d", err);
>  		return err;
> @@ -193,7 +216,7 @@ int vpu_dec_init(struct vdec_vpu_inst *vpu)
>  	if (vpu->ctx->dev->vdec_pdata->hw_arch == MTK_VDEC_LAT_SINGLE_CORE) {
>  		err = mtk_vcodec_fw_ipi_register(vpu->ctx->dev->fw_handler,
>  						 vpu->core_id, vpu->handler,
> -						 "vdec", NULL);
> +						 "vdec", vpu->ctx->dev);
>  		if (err) {
>  			mtk_vdec_err(vpu->ctx, "vpu_ipi_register core fail status=%d", err);
>  			return err;