Okay, I need to classify this bug report: "x86_64 cmpxchg behavior in qemu tcg does not match the real CPU". Let me break it down. First, the issue is about the cmpxchg instruction on x86_64. QEMU uses TCG (Translation Code Generator) for emulating instructions when running in user mode without KVM. The problem here is that the behavior of this specific instruction in TCG doesn't match what a real CPU does. Looking at the categories, 'mistranslation' refers to incorrect semantic mapping from source architecture to IR/target, which happens in user-mode assembly lowering. Since cmpxchg isn't being translated correctly by TCG, this seems like a mistranslation issue. Other categories don't fit as well. It's not related to device, graphic, socket, network, etc. It's also specific to the instruction translation rather than broader issues like performance or kernel problems. mistranslation