Debarshi Dutta 667867a199 gpu: nvgpu: Resolve failed cond init. ...

Following changes are added to fix the issue.

1) Threads having higher priority e.g. RT may preempt
threads with sched-normal priority. As a consequence, higher priority
threads might not still see initialization of data in another thread
resulting in failures such as accessing a condition value before initialization.

Any initialization in the parent thread must be accompanied by a barrier
to make it visible in other thread. Added appropriate barriers to prevent
reordering of the initialization in the thread construction path.

2) There is a race condition between nvgpu_cond_signal() and
nvgpu_cond_destroy() in the asynchronous submit code and corresponding
worker thread's process_item callback for NVS. This may lead to
data corruption and resulting in the above errors as well. Fixed
that by adding a refcount based mechanism for ownership sharing
of the struct nvgpu_nvs_worker_item between the two threads.

Bug 3778235

Signed-off-by: Debarshi Dutta <ddutta@nvidia.com>
Change-Id: Ie9b9ba57bc1dcbb8780801be79863adc39690f72
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2771535
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: svc-mobile-cert <svc-mobile-cert@nvidia.com>
Reviewed-by: Prateek Sethi <prsethi@nvidia.com>
Reviewed-by: Ketan Patil <ketanp@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>

2022-09-27 23:25:55 -07:00

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