[PATCH 07/24] drm/amdkfd: check pcs_enrty valid

[Felix Kuehling]

On 2023-11-03 09:11, James Zhu wrote:
> Check pcs_enrty valid for pc sampling ioctl.
>
> Signed-off-by: James Zhu <James.Zhu at amd.com>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.c | 30 ++++++++++++++++++--
>   1 file changed, 27 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.c b/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.c
> index 4c9fc48e1a6a..36366c8847de 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_pc_sampling.c
> @@ -179,6 +179,21 @@ static int kfd_pc_sample_destroy(struct kfd_process_device *pdd, uint32_t trace_
>   int kfd_pc_sample(struct kfd_process_device *pdd,
>   					struct kfd_ioctl_pc_sample_args __user *args)
>   {
> +	struct pc_sampling_entry *pcs_entry;
> +
> +	if (args->op != KFD_IOCTL_PCS_OP_QUERY_CAPABILITIES &&
> +		args->op != KFD_IOCTL_PCS_OP_CREATE) {
> +
> +		mutex_lock(&pdd->dev->pcs_data.mutex);
> +		pcs_entry = idr_find(&pdd->dev->pcs_data.hosttrap_entry.base.pc_sampling_idr,
> +				args->trace_id);
> +		mutex_unlock(&pdd->dev->pcs_data.mutex);

You need to keep holding the lock while the pcs_entry is still used. 
That includes any of the kfd_pc_sample_<op> functions below. Otherwise 
someone could free it concurrently. It would also simplify the ..._<op> 
functions, if they didn't have to worry about the locking themselves.

Regards,
   Felix


> +
> +		if (!pcs_entry ||
> +			pcs_entry->pdd != pdd)
> +			return -EINVAL;
> +	}
> +
>   	switch (args->op) {
>   	case KFD_IOCTL_PCS_OP_QUERY_CAPABILITIES:
>   		return kfd_pc_sample_query_cap(pdd, args);
> @@ -187,13 +202,22 @@ int kfd_pc_sample(struct kfd_process_device *pdd,
>   		return kfd_pc_sample_create(pdd, args);
>   
>   	case KFD_IOCTL_PCS_OP_DESTROY:
> -		return kfd_pc_sample_destroy(pdd, args->trace_id);
> +		if (pcs_entry->enabled)
> +			return -EBUSY;
> +		else
> +			return kfd_pc_sample_destroy(pdd, args->trace_id);
>   
>   	case KFD_IOCTL_PCS_OP_START:
> -		return kfd_pc_sample_start(pdd);
> +		if (pcs_entry->enabled)
> +			return -EALREADY;
> +		else
> +			return kfd_pc_sample_start(pdd);
>   
>   	case KFD_IOCTL_PCS_OP_STOP:
> -		return kfd_pc_sample_stop(pdd);
> +		if (!pcs_entry->enabled)
> +			return -EALREADY;
> +		else
> +			return kfd_pc_sample_stop(pdd);
>   	}
>   
>   	return -EINVAL;