panic when calling cpunum() with interrupts enabled

929a4d12 · Nickolai Zeldovich · 9621812e · 929a4d12
--- a/kernel/lapic.cc
+++ b/kernel/lapic.cc
@@ -142,17 +142,11 @@ cpunum(void)
 {
  // Cannot call cpu when interrupts are enabled:
  // result not guaranteed to last long enough to be used!
-  // Would prefer to panic but even printing is chancy here:
-  // almost everything, including cprintf and panic, calls cpu,
-  // often indirectly through acquire and release.
  if(readrflags()&FL_IF){
-    static int n __mpalign__;
+    cli();
-    if(n == 0) {
+    panic("cpunum() called from %p with interrupts enabled\n",
-      n++;
-      cprintf("cpu called from %p with interrupts enabled\n",
      __builtin_return_address(0));
  }
-  }
  if(lapic)
    return lapic[ID]>>24;