5.4-stable review patch. If anyone has any objections, please let me know.
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From: Philip Yang Philip.Yang@amd.com
[ 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 Philip.Yang@amd.com Reviewed-by: Felix Kuehling felix.kuehling@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/amd/amdkfd/kfd_process.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c index 662e4d973f13a..b07deeb987475 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c @@ -277,6 +277,14 @@ 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 @@ -289,14 +297,6 @@ 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;