From: Philip Yang Date: Tue, 18 Feb 2025 01:08:29 +0000 (-0500) Subject: drm/amdkfd: KFD release_work possible circular locking X-Git-Tag: v5.10.238~94 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=370e39467a83237f9882f7a04cca5d8f039d7e96;p=thirdparty%2Fkernel%2Fstable.git drm/amdkfd: KFD release_work possible circular locking [ Upstream commit 1b9366c601039d60546794c63fbb83ce8e53b978 ] If waiting for gpu reset done in KFD release_work, thers is WARNING: possible circular locking dependency detected #2 kfd_create_process kfd_process_mutex flush kfd release work #1 kfd release work wait for amdgpu reset work #0 amdgpu_device_gpu_reset kgd2kfd_pre_reset kfd_process_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((work_completion)(&p->release_work)); lock((wq_completion)kfd_process_wq); lock((work_completion)(&p->release_work)); lock((wq_completion)amdgpu-reset-dev); To fix this, KFD create process move flush release work outside kfd_process_mutex. Signed-off-by: Philip Yang Reviewed-by: Felix Kuehling Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c index 184527afe2bd5..05d2598f516d1 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c @@ -755,6 +755,14 @@ struct kfd_process *kfd_create_process(struct file *filep) if (thread->group_leader->mm != 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. + * Make sure to drain any job before trying to recreate any + * resource for this process. + */ + flush_workqueue(kfd_process_wq); + /* * take kfd processes mutex before starting of process creation * so there won't be a case where two threads of the same process @@ -767,14 +775,6 @@ struct kfd_process *kfd_create_process(struct file *filep) if (process) { pr_debug("Process already found\n"); } else { - /* 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. - * Make sure to drain any job before trying to recreate any - * resource for this process. - */ - flush_workqueue(kfd_process_wq); - process = create_process(thread); if (IS_ERR(process)) goto out;