From: Philip Yang Date: Tue, 27 May 2025 15:09:53 +0000 (-0400) Subject: drm/amdkfd: Fix kfd process ref leaking when userptr unmapping X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=58e6fc2fb94f0f409447e5d46cf6a417b6397fbc;p=users%2Fhch%2Fmisc.git drm/amdkfd: Fix kfd process ref leaking when userptr unmapping kfd_lookup_process_by_pid hold the kfd process reference to ensure it doesn't get destroyed while sending the segfault event to user space. Calling kfd_lookup_process_by_pid as function parameter leaks the kfd process refcount and miss the NULL pointer check if app process is already destroyed. Fixes: 2d274bf7099b ("amd/amdkfd: Trigger segfault for early userptr unmmapping") Signed-off-by: Philip Yang Reviewed-by: Harish Kasiviswanathan Signed-off-by: Alex Deucher --- diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 7c54fe6b0f5d..83020963dfde 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -2586,12 +2586,17 @@ static int update_invalid_user_pages(struct amdkfd_process_info *process_info, * from the KFD, trigger a segmentation fault in VM debug mode. */ if (amdgpu_ttm_adev(bo->tbo.bdev)->debug_vm_userptr) { + struct kfd_process *p; + 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); + p = kfd_lookup_process_by_pid(process_info->pid); + if (p) { + kfd_signal_vm_fault_event_with_userptr(p, mem->va); + kfd_unref_process(p); + } } ret = 0;