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@xxxxxxx>
Reviewed-by: Felix Kuehling <felix.kuehling@xxxxxxx>
---
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 1067afdb456e..2715ca53e9da 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -838,6 +838,14 @@ struct kfd_process *kfd_create_process(struct task_struct *thread)
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
@@ -858,14 +866,6 @@ struct kfd_process *kfd_create_process(struct task_struct *thread)
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;
--
2.47.1
