Hang in testUsdThreadedAuthoring with 23.02 on Windows

[pmolodo]

Description of Issue

We're seeing semi-frequent hangs of testUsdThreadedAuthoring with 23.02 windows builds.

I'm attaching a minidump, and printout of the call stacks for all the threads, and a summary of where all the threads are blocking.

testUsdThreadedAuthoring.noHeap.dmp.zip
testUsdThreadedAuthoring.threadCallStacks.txt
testUsdThreadedAuthoring.threadCallStacks.summary.txt

It looks like there’s an issue with the TfBigRWMutex on the Tf_TypeRegistry - it hangs trying to get a write lock, in _WaitForReaders. I could see in the debugger that on the TfBigRWMutex , _states[2].mutex._lockState == 3, which meant it had already acquired the write lock, but there was one read lock that wouldn’t free. No other threads had a read lock that I could see, though - so I'm not precisely sure what's going on.

Steps to Reproduce

1. Build v23.02 on windows
2. Keep running testUsdThreadedAuthoring until it hangs.

System Information (OS, Hardware)

Windows

Package Versions

v23.02 (tagged release)

[tallytalwar]

Filed as internal issue #USD-8020