cpu: ensure we don't call start_exclusive from cpu_exec

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20241025175857.2554252-3-pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

cpu-common.c

@@ -194,6 +194,9 @@ void start_exclusive(void)
     CPUState *other_cpu;
     int running_cpus;
 
+    /* Ensure we are not running, or start_exclusive will be blocked. */
+    g_assert(!current_cpu->running);
+
     if (current_cpu->exclusive_context_count) {
         current_cpu->exclusive_context_count++;
         return;