From b6cac0a53b45a8f35e348dc3235243c066aab747 Mon Sep 17 00:00:00 2001
From: rsc <rsc>
Date: Thu, 7 Sep 2006 16:54:00 +0000
Subject: [PATCH] check preconditions in sched

---
 proc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/proc.c b/proc.c
index 37fd768..e48f1ca 100644
--- a/proc.c
+++ b/proc.c
@@ -207,6 +207,11 @@ sched(void)
 {
   struct proc *p = curproc[cpu()];
 
+  if(!holding(&proc_table_lock))
+    panic("sched");
+  if(cpus[cpu()].nlock != 1)
+    panic("sched locks");
+
   if(setjmp(&p->jmpbuf) == 0)
     longjmp(&cpus[cpu()].jmpbuf);
 }