1 files changed, 14 insertions, 2 deletions
diff --git a/trap.c b/trap.c
index 01c2f14..e36540d 100644
--- a/trap.c
+++ b/trap.c
@@ -35,16 +35,28 @@ trap(struct Trapframe *tf)
 {
   int v = tf->tf_trapno;
 
+  if(tf->tf_cs == 0x8 && kernel_lock == cpu())
+    cprintf("cpu %d: trap from %x:%x with lock=%d\n",
+            cpu(), tf->tf_cs, tf->tf_eip, kernel_lock);
+
   acquire_spinlock(&kernel_lock); // released in trapret in trapasm.S
 
   if(v == T_SYSCALL){
-    curproc[cpu()]->tf = tf;
+    struct proc *cp = curproc[cpu()];
+    cp->tf = tf;
     syscall();
+    if(cp != curproc[cpu()])
+      panic("trap ret wrong curproc");
+    if(cp->state != RUNNING)
+      panic("trap ret but not RUNNING");
+    if(tf != cp->tf)
+      panic("trap ret wrong tf");
+    if(read_esp() < cp->kstack || read_esp() >= cp->kstack + KSTACKSIZE)
+      panic("trap ret esp wrong");
     return;
   }
 
   if(v == (IRQ_OFFSET + IRQ_TIMER)){
-    curproc[cpu()]->tf = tf;
     lapic_timerintr();
     return;
   }