Hi Haris, this is a known issue. We’ve been working on fixing it. The problem is that the pthreadpool runs into a deadlock situation when running resnet50.  There are a couple of work around for it, you can try

Set the number of thread to one in ThreadPool.cc
Use a different mutex in int ThreadPool::getNumThreads() const function
Use std::unique_lock<std::mutex> guard(executionMutex_, std::defer_lock); instead

Then recompile the PyTorch from source code by following the link here - https://pytorch.org/mobile/ios/#build-pytorch-ios-libraries-from-source 3.