[PATCH 2/2] drm/amd/display: fix null pointer access in gpu reset

[Harry Wentland]

On 2021-06-28 5:27 a.m., Guchun Chen wrote:
> During GPU reset, when receiving a DMCUB OUTBUX0 interrupt,
> DAL code will set it to be OUTBOX interrupt and sets hw interrupt.
> However, OUTBOX interrupt is not registered yet, so a NULL pointer
> access will be executed.
> 
> Call Trace:
>   dal_irq_service_set+0x30/0x90 [amdgpu]
>   dc_interrupt_set+0x24/0x30 [amdgpu]
>   amdgpu_dm_set_dmub_outbox_irq_state+0x22/0x30 [amdgpu]
>   amdgpu_irq_update+0x77/0xa0 [amdgpu]
>   amdgpu_irq_gpu_reset_resume_helper+0x67/0xa0 [amdgpu]
>   amdgpu_do_asic_reset+0x219/0x260 [amdgpu]
>   amdgpu_device_gpu_recover.cold+0x8c5/0xb64 [amdgpu]
>   amdgpu_debugfs_gpu_recover_show+0x2c/0x60 [amdgpu]
>   seq_read_iter+0xc2/0x450
>   ? do_anonymous_page+0x22c/0x3b0
>   seq_read+0xf9/0x140
>   full_proxy_read+0x5c/0x90
>   vfs_read+0xaa/0x190
>   ksys_read+0x67/0xe0
>   __x64_sys_read+0x1a/0x20
> 
> Fixes: 85465bd6dc6e drm/amdgpu/display: remove an old DCN3 guard
> 
> Signed-off-by: Guchun Chen <guchun.chen at amd.com>

Series is
Reviewed-by: Harry Wentland <harry.wentland at amd.com>

Harry

> ---
>  drivers/gpu/drm/amd/display/dc/irq/irq_service.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/irq/irq_service.c b/drivers/gpu/drm/amd/display/dc/irq/irq_service.c
> index 5f245bde54ff..a2a4fbeb83f8 100644
> --- a/drivers/gpu/drm/amd/display/dc/irq/irq_service.c
> +++ b/drivers/gpu/drm/amd/display/dc/irq/irq_service.c
> @@ -119,7 +119,7 @@ bool dal_irq_service_set(
>  
>  	dal_irq_service_ack(irq_service, source);
>  
> -	if (info->funcs->set)
> +	if (info->funcs && info->funcs->set)
>  		return info->funcs->set(irq_service, info, enable);
>  
>  	dal_irq_service_set_generic(irq_service, info, enable);
> @@ -153,7 +153,7 @@ bool dal_irq_service_ack(
>  		return false;
>  	}
>  
> -	if (info->funcs->ack)
> +	if (info->funcs && info->funcs->ack)
>  		return info->funcs->ack(irq_service, info);
>  
>  	dal_irq_service_ack_generic(irq_service, info);
>