[PATCH 1/1] drm/amdgpu: Move reset domain init before calling RREG32

[Andrey Grodzovsky]

Reviewed-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>

Andrey

On 2022-03-11 10:15, Philip Yang wrote:
> amdgpu_detect_virtualization reads register, amdgpu_device_rreg access
> adev->reset_domain->sem if kernel defined CONFIG_LOCKDEP, below is the
> random boot hang backtrace on Vega10. It may get random NULL pointer
> access backtrace if amdgpu_sriov_runtime is true too.
>
> Move amdgpu_reset_create_reset_domain before calling to RREG32.
>
>   BUG: kernel NULL pointer dereference, address:
>   #PF: supervisor read access in kernel mode
>   #PF: error_code(0x0000) - not-present page
>   PGD 0 P4D 0
>   Oops: 0000 [#1] PREEMPT SMP NOPTI
>   Workqueue: events work_for_cpu_fn
>   RIP: 0010:down_read_trylock+0x13/0xf0
>   Call Trace:
>    <TASK>
>    amdgpu_device_skip_hw_access+0x38/0x80 [amdgpu]
>    amdgpu_device_rreg+0x1b/0x170 [amdgpu]
>    amdgpu_detect_virtualization+0x73/0x100 [amdgpu]
>    amdgpu_device_init.cold.60+0xbe/0x16b1 [amdgpu]
>    ? pci_bus_read_config_word+0x43/0x70
>    amdgpu_driver_load_kms+0x15/0x120 [amdgpu]
>    amdgpu_pci_probe+0x1a1/0x3a0 [amdgpu]
>
> Fixes: 1228996f0 ("drm/amdgpu: Move reset sem into reset_domain")
> Signed-off-by: Philip Yang <Philip.Yang at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 18 +++++++++---------
>   1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 71876ff466df..a35c6acfe2ab 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -3665,6 +3665,15 @@ int amdgpu_device_init(struct amdgpu_device *adev,
>   	if (amdgpu_mes && adev->asic_type >= CHIP_NAVI10)
>   		adev->enable_mes = true;
>   
> +	/*
> +	 * Reset domain needs to be present early, before XGMI hive discovered
> +	 * (if any) and intitialized to use reset sem and in_gpu reset flag
> +	 * early on during init and before calling to RREG32.
> +	 */
> +	adev->reset_domain = amdgpu_reset_create_reset_domain(SINGLE_DEVICE, "amdgpu-reset-dev");
> +	if (!adev->reset_domain)
> +		return -ENOMEM;
> +
>   	/* detect hw virtualization here */
>   	amdgpu_detect_virtualization(adev);
>   
> @@ -3674,15 +3683,6 @@ int amdgpu_device_init(struct amdgpu_device *adev,
>   		return r;
>   	}
>   
> -	/*
> -	 * Reset domain needs to be present early, before XGMI hive discovered
> -	 * (if any) and intitialized to use reset sem and in_gpu reset flag
> -	 * early on during init.
> -	 */
> -	adev->reset_domain = amdgpu_reset_create_reset_domain(SINGLE_DEVICE, "amdgpu-reset-dev");
> -	if (!adev->reset_domain)
> -		return -ENOMEM;
> -
>   	/* early init functions */
>   	r = amdgpu_device_ip_early_init(adev);
>   	if (r)