On 5/25/26 10:23, Zhu Lingshan wrote:
> MES process context is a process-level page
> where process specific context is saved for
> MES scheduler.
>
> However, current user-queue code path assigns
> fw_obj of a queue to MES process_context_addr
> when adding the queue to MES.
>
> This means every new queue from the same process
> would replace the previous process context address
> with that queue's fw_obj address.
> What's worse is, when user space frees a queue,
> its fw_obj will be freed as well, causing MES
> working on a NULL page pointer.
>
> This issue leads to inconsistency and crash
> in the scheduler.
>
> This commit allocates a process-level page for
> MES process contexts for a process other than queue-level
>
> Signed-off-by: Zhu Lingshan <[email protected]>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c | 5 +++
> drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h | 1 +
> drivers/gpu/drm/amd/amdgpu/mes_userqueue.c | 48 ++++++++++++++++------
> 3 files changed, 42 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> index 38e310a8694d..0c4d6f80616e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
> @@ -1225,6 +1225,11 @@ void amdgpu_userq_mgr_fini(struct amdgpu_userq_mgr
> *userq_mgr)
> */
> cancel_work_sync(&userq_mgr->reset_work);
>
> + if (userq_mgr->proc_ctx_obj.obj)
Please drop that check it is unecessary.
> + amdgpu_bo_free_kernel(&userq_mgr->proc_ctx_obj.obj,
> + &userq_mgr->proc_ctx_obj.gpu_addr,
> + &userq_mgr->proc_ctx_obj.cpu_ptr);
> +
> mutex_destroy(&userq_mgr->userq_mutex);
> }
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h
> index 28cfc6682333..fe85234e58b3 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h
> @@ -127,6 +127,7 @@ struct amdgpu_userq_mgr {
> struct amdgpu_device *adev;
> struct delayed_work resume_work;
> struct drm_file *file;
> + struct amdgpu_userq_obj proc_ctx_obj;
>
> /**
> * @reset_work:
> diff --git a/drivers/gpu/drm/amd/amdgpu/mes_userqueue.c
> b/drivers/gpu/drm/amd/amdgpu/mes_userqueue.c
> index e9189f07c6dc..3022025bc2ec 100644
> --- a/drivers/gpu/drm/amd/amdgpu/mes_userqueue.c
> +++ b/drivers/gpu/drm/amd/amdgpu/mes_userqueue.c
> @@ -133,8 +133,8 @@ static int mes_userq_map(struct amdgpu_usermode_queue
> *queue)
> queue_input.gang_quantum = 10000;
> queue_input.paging = false;
>
> - queue_input.process_context_addr = ctx->gpu_addr;
> - queue_input.gang_context_addr = ctx->gpu_addr +
> AMDGPU_USERQ_PROC_CTX_SZ;
> + queue_input.process_context_addr = uq_mgr->proc_ctx_obj.gpu_addr;
> + queue_input.gang_context_addr = ctx->gpu_addr;
> queue_input.inprocess_gang_priority = AMDGPU_MES_PRIORITY_LEVEL_NORMAL;
> queue_input.gang_global_priority_level =
> convert_to_mes_priority(queue->priority);
>
> @@ -169,7 +169,7 @@ static int mes_userq_unmap(struct amdgpu_usermode_queue
> *queue)
>
> memset(&queue_input, 0x0, sizeof(struct mes_remove_queue_input));
> queue_input.doorbell_offset = queue->doorbell_index;
> - queue_input.gang_context_addr = ctx->gpu_addr +
> AMDGPU_USERQ_PROC_CTX_SZ;
> + queue_input.gang_context_addr = ctx->gpu_addr;
>
> amdgpu_mes_lock(&adev->mes);
> r = adev->mes.funcs->remove_hw_queue(&adev->mes, &queue_input);
> @@ -186,12 +186,8 @@ static int mes_userq_create_ctx_space(struct
> amdgpu_userq_mgr *uq_mgr,
> struct amdgpu_userq_obj *ctx = &queue->fw_obj;
> int r, size;
>
> - /*
> - * The FW expects at least one page space allocated for
> - * process ctx and gang ctx each. Create an object
> - * for the same.
> - */
> - size = AMDGPU_USERQ_PROC_CTX_SZ + AMDGPU_USERQ_GANG_CTX_SZ;
> + /* The FW expects at least one page space allocated for gang ctx. */
> + size = AMDGPU_USERQ_GANG_CTX_SZ;
> r = amdgpu_bo_create_kernel(uq_mgr->adev, size, 0,
> AMDGPU_GEM_DOMAIN_GTT,
> &ctx->obj, &ctx->gpu_addr,
> @@ -257,6 +253,27 @@ static int mes_userq_detect_and_reset(struct
> amdgpu_device *adev,
> return r;
> }
>
> +static int mes_userq_create_proc_ctx_space(struct amdgpu_userq_mgr *uq_mgr)
> +{
> + int r = 0;
> +
> + mutex_lock(&uq_mgr->userq_mutex);
Clear NAK. We can't allocate anything while holding that lock.
Please add a different lock to protected the buffer or just oportunistically
allocate it with CMPXCHG().
> + if (!uq_mgr->proc_ctx_obj.obj) {
Please drop that check, amdgpu_bo_create_kernel() should already take care of
that.
Regards,
Christian.
> + r = amdgpu_bo_create_kernel(uq_mgr->adev,
> AMDGPU_USERQ_PROC_CTX_SZ,
> + 0, AMDGPU_GEM_DOMAIN_GTT,
> + &uq_mgr->proc_ctx_obj.obj,
> + &uq_mgr->proc_ctx_obj.gpu_addr,
> + &uq_mgr->proc_ctx_obj.cpu_ptr);
> +
> + if (!r)
> + memset(uq_mgr->proc_ctx_obj.cpu_ptr, 0,
> AMDGPU_USERQ_PROC_CTX_SZ);
> + }
> +
> + mutex_unlock(&uq_mgr->userq_mutex);
> +
> + return r;
> +}
> +
> static int mes_userq_mqd_create(struct amdgpu_usermode_queue *queue,
> struct drm_amdgpu_userq_in *args_in)
> {
> @@ -429,7 +446,14 @@ static int mes_userq_mqd_create(struct
> amdgpu_usermode_queue *queue,
> goto free_mqd;
> }
>
> - /* Create BO for FW operations */
> + /* Create per-process MES process context BO */
> + r = mes_userq_create_proc_ctx_space(uq_mgr);
> + if (r) {
> + DRM_ERROR("Failed to allocate MES process context space bo,
> error: %d\n", r);
> + goto free_mqd;
> + }
> +
> + /* Create BO of a gang for FW operations */
> r = mes_userq_create_ctx_space(uq_mgr, queue, mqd_user);
> if (r) {
> DRM_ERROR("Failed to allocate BO for userqueue (%d)", r);
> @@ -492,7 +516,7 @@ static int mes_userq_preempt(struct amdgpu_usermode_queue
> *queue)
> *fence_ptr = 0;
>
> memset(&queue_input, 0x0, sizeof(struct mes_suspend_gang_input));
> - queue_input.gang_context_addr = ctx->gpu_addr +
> AMDGPU_USERQ_PROC_CTX_SZ;
> + queue_input.gang_context_addr = ctx->gpu_addr;
> queue_input.suspend_fence_addr = fence_gpu_addr;
> queue_input.suspend_fence_value = 1;
> amdgpu_mes_lock(&adev->mes);
> @@ -529,7 +553,7 @@ static int mes_userq_restore(struct amdgpu_usermode_queue
> *queue)
> return 0;
>
> memset(&queue_input, 0x0, sizeof(struct mes_resume_gang_input));
> - queue_input.gang_context_addr = ctx->gpu_addr +
> AMDGPU_USERQ_PROC_CTX_SZ;
> + queue_input.gang_context_addr = ctx->gpu_addr;
>
> amdgpu_mes_lock(&adev->mes);
> r = adev->mes.funcs->resume_gang(&adev->mes, &queue_input);
