Index: sys/kern/kern_exec.c
===================================================================
--- sys/kern/kern_exec.c
+++ sys/kern/kern_exec.c
@@ -174,6 +174,7 @@
 static int
 sysctl_kern_usrstack(SYSCTL_HANDLER_ARGS)
 {
+	vm_offset_t stackaddr;
 	struct proc *p;
 	int error;
 
@@ -181,12 +182,15 @@
 #ifdef SCTL_MASK32
 	if (req->flags & SCTL_MASK32) {
 		unsigned int val;
-		val = (unsigned int)p->p_sysent->sv_usrstack;
+		val = (unsigned int)p->p_sysent->sv_usrstack
+		    - p->p_vmspace->vm_stkgap;
 		error = SYSCTL_OUT(req, &val, sizeof(val));
 	} else
 #endif
-		error = SYSCTL_OUT(req, &p->p_sysent->sv_usrstack,
-		    sizeof(p->p_sysent->sv_usrstack));
+	{
+		stackaddr = p->p_sysent->sv_usrstack - p->p_vmspace->vm_stkgap;
+		error = SYSCTL_OUT(req, &stackaddr, sizeof(stackaddr));
+	}
 	return error;
 }