Re: [PATCH 0/3] MR87: vkd3d: Hold locks to read protected variables

[Conor McCarthy (＠cmccarthy)]

My understanding of the problem with blocked_queue_count is this sequence:

1. thread0: Is in d3d12_command_queue_Wait() after `if (!command_queue->ops_count && value <= fence->max_pending_value)` but has not yet called d3d12_device_add_blocked_command_queues().
2. thread1: Is handling a signal which unblocks the wait, but had not yet updated max_pending_value when thread0 checked it. It executes `if (!device->blocked_queue_count)` before thread0 calls  d3d12_device_add_blocked_command_queues().
3. thread0: calls d3d12_device_add_blocked_command_queues() but the corresponding call to d3d12_device_flush_blocked_queues() has passed in thread1.