From 2d274bf7099bc5e95fabaa93f23d0eb2977187ad Mon Sep 17 00:00:00 2001 From: Shane Xiao Date: Wed, 23 Apr 2025 17:28:50 +0800 Subject: [PATCH] amd/amdkfd: Trigger segfault for early userptr unmmapping MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit If applications unmap the memory before destroying the userptr, it needs trigger a segfault to notify user space to correct the free sequence in VM debug mode. v2: Send gpu access fault to user space v3: Report gpu address to user space, remove unnecessary params v4: update pr_err into one line, remove userptr log info Signed-off-by: Shane Xiao Acked-by: Christian König Reviewed-by: Felix Kuehling Signed-off-by: Alex Deucher --- .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 12 ++++++++++++ drivers/gpu/drm/amd/amdkfd/kfd_events.c | 19 +++++++++++++++++++ drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 2 ++ 3 files changed, 33 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index d2ec4130a316d..260165bbe3736 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -2559,6 +2559,18 @@ static int update_invalid_user_pages(struct amdkfd_process_info *process_info, if (ret != -EFAULT) return ret; + /* If applications unmap memory before destroying the userptr + * from the KFD, trigger a segmentation fault in VM debug mode. + */ + if (amdgpu_ttm_adev(bo->tbo.bdev)->debug_vm_userptr) { + pr_err("Pid %d unmapped memory before destroying userptr at GPU addr 0x%llx\n", + pid_nr(process_info->pid), mem->va); + + // Send GPU VM fault to user space + kfd_signal_vm_fault_event_with_userptr(kfd_lookup_process_by_pid(process_info->pid), + mem->va); + } + ret = 0; } diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_events.c index fecdb67940750..e54e708ed82de 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_events.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.c @@ -1177,6 +1177,25 @@ void kfd_signal_hw_exception_event(u32 pasid) kfd_unref_process(p); } +void kfd_signal_vm_fault_event_with_userptr(struct kfd_process *p, uint64_t gpu_va) +{ + struct kfd_process_device *pdd; + struct kfd_hsa_memory_exception_data exception_data; + int i; + + memset(&exception_data, 0, sizeof(exception_data)); + exception_data.va = gpu_va; + exception_data.failure.NotPresent = 1; + + // Send VM seg fault to all kfd process device + for (i = 0; i < p->n_pdds; i++) { + pdd = p->pdds[i]; + exception_data.gpu_id = pdd->user_gpu_id; + kfd_evict_process_device(pdd); + kfd_signal_vm_fault_event(pdd, NULL, &exception_data); + } +} + void kfd_signal_vm_fault_event(struct kfd_process_device *pdd, struct kfd_vm_fault_info *info, struct kfd_hsa_memory_exception_data *data) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h index 0ae794539bb0a..d221c58dccc3c 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h @@ -1507,6 +1507,8 @@ int kfd_event_create(struct file *devkfd, struct kfd_process *p, int kfd_get_num_events(struct kfd_process *p); int kfd_event_destroy(struct kfd_process *p, uint32_t event_id); +void kfd_signal_vm_fault_event_with_userptr(struct kfd_process *p, uint64_t gpu_va); + void kfd_signal_vm_fault_event(struct kfd_process_device *pdd, struct kfd_vm_fault_info *info, struct kfd_hsa_memory_exception_data *data); -- 2.39.5