Re: [PATCH 4/7] drm/amd: kill the outdated "Only the pthreads threading model is supported" checks

[Felix Kuehling <felix.kuehling@amd.com>]

On 2025-12-07 07:39, Oleg Nesterov wrote:
> Nowaday task->group_leader->mm != task->mm is only possible if
> a) task is not a group leader and b) task->group_leader->mm == NULL
> because task->group_leader has already exited using sys_exit().
>
> I don't think that drm/amd tries to detect/nack this case.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Acked-by: Felix Kuehling <felix.kuehling@amd.com>


> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c   |  3 ---
>   drivers/gpu/drm/amd/amdkfd/kfd_process.c | 10 ----------
>   2 files changed, 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index a0f8ba382b9e..e44f158a11f0 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -2551,9 +2551,6 @@ void amdgpu_vm_set_task_info(struct amdgpu_vm *vm)
>   	vm->task_info->task.pid = current->pid;
>   	get_task_comm(vm->task_info->task.comm, current);
>   
> -	if (current->group_leader->mm != current->mm)
> -		return;
> -
>   	vm->task_info->tgid = current->tgid;
>   	get_task_comm(vm->task_info->process_name, current->group_leader);
>   }
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> index a085faac9fe1..f8ef18a3aa71 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> @@ -833,12 +833,6 @@ struct kfd_process *kfd_create_process(struct task_struct *thread)
>   	if (!(thread->mm && mmget_not_zero(thread->mm)))
>   		return ERR_PTR(-EINVAL);
>   
> -	/* Only the pthreads threading model is supported. */
> -	if (thread->group_leader->mm != thread->mm) {
> -		mmput(thread->mm);
> -		return ERR_PTR(-EINVAL);
> -	}
> -
>   	/* If the process just called exec(3), it is possible that the
>   	 * cleanup of the kfd_process (following the release of the mm
>   	 * of the old process image) is still in the cleanup work queue.
> @@ -918,10 +912,6 @@ struct kfd_process *kfd_get_process(const struct task_struct *thread)
>   	if (!thread->mm)
>   		return ERR_PTR(-EINVAL);
>   
> -	/* Only the pthreads threading model is supported. */
> -	if (thread->group_leader->mm != thread->mm)
> -		return ERR_PTR(-EINVAL);
> -
>   	process = find_process(thread, false);
>   	if (!process)
>   		return ERR_PTR(-EINVAL);