Change proc state under held spinlock

kernel/syscall/proc.c

@@ -125,7 +125,9 @@ int32_t SYSCALL1(sys_proc_run, pid1) {
     goto done;
   }
 
+  spinlock_acquire(&PROCS.spinlock);
   proc->state = PROC_READY;  
+  spinlock_release(&PROCS.spinlock);
 
 done:
   return ret;