lock user-mode and semantic-bugs

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+x86_64 emu on aarch64 host: cpu_exec: assertion failed: (cpu == current_cpu)
+Description of problem:
+Execution of some binaries crashes with `Bail out! ERROR:../qemu-7.0.0/accel/tcg/cpu-exec.c:933:cpu_exec: assertion failed: (cpu == current_cpu)`. Looking at the code, that code is wrapped in a gcc/clang ifdef. Recompiling with clang produces this crash instead: `... include/qemu/rcu.h:102: void rcu_read_unlock(void): Assertion 'p_rcu_reader->depth != 0' failed.`
+
+No easier steps to reproduce (yet) than `systemd-nspawn`ing into an x86_64 Ubuntu container invoking qemu-x86_64-static through binfmt. Commands such as `ls` work fine, while `apt-get` will immediately crash with the error listed above.
+
+Note that this happens running Asahi Linux on the bare metal of an M1-based Macbook Pro. This same issue does *not* occur running the *same* binaries with the *same* x86_64 Ubuntu image on an Arch or Ubuntu VM under macOS on the same machine - regardless of if the QEMU binaries were built in a VM or in Asahi.
+
+These are big.LITTLE chips. Using taskset/affinity to limit the target process to a single specific core does not help. The Asahi kernel has a 16K page-size, which is known to cause trouble for some programs. qemu-arm(-static) however works without any issues (the M1 cannot run 32-bit ARM code natively, only 64-bit).