[llvm] [Offload] Fix self-deadlock on RPC initialization (PR #219012)

[Kevin Sala Penades via llvm-commits]

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@@ -236,6 +238,7 @@ Error RPCServerTy::initDevice(plugin::GenericDeviceTy &Device,
         static_cast<uint8_t *>(RPCBuffer) + rpc::Server::doorbell_offset());
     std::memcpy(DoorbellPtr, &Doorbell, sizeof(rpc::Doorbell));
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kevinsala wrote:

Is it possible that two threads call `initDevice` passing the same device in parallel?

https://github.com/llvm/llvm-project/pull/219012