Re: [PATCH v1, 6/8] media: mtk-vcodec: prevent kernel crash when scp ipi timeout

[Macpaul Lin <macpaul.lin@mediatek.com>]

On 1/27/22 10:55 AM, Yunfei Dong wrote:
> From: Tinghan Shen <tinghan.shen@mediatek.com>
> 
> When SCP timeout during playing video, kernel crashes with following
> message. It's caused by accessing NULL pointer in vpu_dec_ipi_handler.
> This patch doesn't solve the root cause of NULL pointer, but merely
> prevent kernel crashed when encounter the NULL pointer.
> 
> After applied this patch, kernel keeps alive, only the video player turns
> to green screen.
> 
> [67242.065474] pc : vpu_dec_ipi_handler+0xa0/0xb20 [mtk_vcodec_dec]
> [67242.065485] [MTK_V4L2] level=0 fops_vcodec_open(),334:
> 18000000.vcodec_dec decoder [135]
> [67242.065523] lr : scp_ipi_handler+0x11c/0x244 [mtk_scp]
> [67242.065540] sp : ffffffbb4207fb10
> [67242.065557] x29: ffffffbb4207fb30 x28: ffffffd00a1d5000
> [67242.065592] x27: 1ffffffa0143aa24 x26: 0000000000000000
> [67242.065625] x25: dfffffd000000000 x24: ffffffd0168bfdb0
> [67242.065659] x23: 1ffffff76840ff74 x22: ffffffbb41fa8a88
> [67242.065692] x21: ffffffbb4207fb9c x20: ffffffbb4207fba0
> [67242.065725] x19: ffffffbb4207fb98 x18: 0000000000000000
> [67242.065758] x17: 0000000000000000 x16: ffffffd042022094
> [67242.065791] x15: 1ffffff77ed4b71a x14: 1ffffff77ed4b719
> [67242.065824] x13: 0000000000000000 x12: 0000000000000000
> [67242.065857] x11: 0000000000000000 x10: dfffffd000000001
> [67242.065890] x9 : 0000000000000000 x8 : 0000000000000002
> [67242.065923] x7 : 0000000000000000 x6 : 000000000000003f
> [67242.065956] x5 : 0000000000000040 x4 : ffffffffffffffe0
> [67242.065989] x3 : ffffffd043b841b8 x2 : 0000000000000000
> [67242.066021] x1 : 0000000000000010 x0 : 0000000000000010
> [67242.066055] Call trace:
> [67242.066092]  vpu_dec_ipi_handler+0xa0/0xb20 [mtk_vcodec_dec
> 12220d230d83a7426fc38c56b3e7bc6066955bae]
> [67242.066119]  scp_ipi_handler+0x11c/0x244 [mtk_scp
> 8fb69c2ef141dd3192518b952b65aba35627b8bf]
> [67242.066145]  mt8192_scp_irq_handler+0x70/0x128 [mtk_scp
> 8fb69c2ef141dd3192518b952b65aba35627b8bf]
> [67242.066172]  scp_irq_handler+0xa0/0x114 [mtk_scp
> 8fb69c2ef141dd3192518b952b65aba35627b8bf]
> [67242.066200]  irq_thread_fn+0x84/0xf8
> [67242.066220]  irq_thread+0x170/0x1ec
> [67242.066242]  kthread+0x2f8/0x3b8
> [67242.066264]  ret_from_fork+0x10/0x30
> [67242.066292] Code: 38f96908 35003628 91004340 d343fc08 (38f96908)
> 
> Signed-off-by: Tinghan Shen <tinghan.shen@mediatek.com>
> Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
> ---
>   drivers/media/platform/mtk-vcodec/vdec_vpu_if.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/media/platform/mtk-vcodec/vdec_vpu_if.c b/drivers/media/platform/mtk-vcodec/vdec_vpu_if.c
> index 35f4d5583084..1041dd663e76 100644
> --- a/drivers/media/platform/mtk-vcodec/vdec_vpu_if.c
> +++ b/drivers/media/platform/mtk-vcodec/vdec_vpu_if.c
> @@ -91,6 +91,11 @@ static void vpu_dec_ipi_handler(void *data, unsigned int len, void *priv)
>   	struct vdec_vpu_inst *vpu = (struct vdec_vpu_inst *)
>   					(unsigned long)msg->ap_inst_addr;
>   
> +	if (!vpu) {
> +		mtk_v4l2_err("ap_inst_addr is NULL");
> +		return;
> +	}
> +
>   	mtk_vcodec_debug(vpu, "+ id=%X", msg->msg_id);
>   
>   	vpu->failure = msg->status;
> 

Reviewed-by: Macpaul Lin <macpaul.lin@mediatek.com>

Regards,
Macpaul Lin