[src/trunk]: src/sys/kern add DIAGNOSTIC check for rnd_attach_source() being ...

[jdolecek <jdolecek%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d7a8547d9fc6
branches:  trunk
changeset: 362963:d7a8547d9fc6
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Tue Jul 03 18:09:28 2018 +0000

description:
add DIAGNOSTIC check for rnd_attach_source() being called twice for same
rnd source; it's driver error, and it breaks rnd source list pointers

diffstat:

 sys/kern/kern_rndq.c |  16 ++++++++++++++--
 1 files changed, 14 insertions(+), 2 deletions(-)

diffs (37 lines):

diff -r 61c534ba8812 -r d7a8547d9fc6 sys/kern/kern_rndq.c
--- a/sys/kern/kern_rndq.c      Tue Jul 03 18:07:36 2018 +0000
+++ b/sys/kern/kern_rndq.c      Tue Jul 03 18:09:28 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_rndq.c,v 1.89 2016/05/21 15:27:15 riastradh Exp $ */
+/*     $NetBSD: kern_rndq.c,v 1.90 2018/07/03 18:09:28 jdolecek Exp $  */
 
 /*-
  * Copyright (c) 1997-2013 The NetBSD Foundation, Inc.
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.89 2016/05/21 15:27:15 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.90 2018/07/03 18:09:28 jdolecek Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -747,6 +747,18 @@
        rs->state = rnd_sample_allocate(rs);
 
        mutex_spin_enter(&rnd_global.lock);
+
+#ifdef DIAGNOSTIC
+       krndsource_t *s;
+       LIST_FOREACH(s, &rnd_global.sources, list) {
+               if (s == rs) {
+                       panic("%s: source '%s' already attached",
+                           __func__, name);
+                       /* NOTREACHED */
+               }
+       }
+#endif
+
        LIST_INSERT_HEAD(&rnd_global.sources, rs, list);
 
 #ifdef RND_VERBOSE