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>- if (!user_return_msrs) { >- pr_err("failed to allocate percpu user_return_msrs\n"); >- return -ENOMEM; >- } >+ int cpu; >+ >+ for_each_possible_cpu(cpu) >+ WARN_ON_ONCE(per_cpu(user_return_msrs, cpu).registered); Could this warning be triggered if the forced shutdown path didn't unregister the user return callback (i.e., with the patch [*] applied), and then vendor modules got unloaded immediately after the forced shutdown (before the CPU exits to the userspace)? [*]: https://lore.kernel.org/kvm/20251030191528.3380553-4-seanjc@google.com/