From 58ea2fbbd48cc91a0db783df650bad9dfcd132e6 Mon Sep 17 00:00:00 2001
From: ad <ad@NetBSD.org>
Date: Sun, 8 Mar 2020 17:04:45 +0000
Subject: [PATCH] PR kern/55020: dbregs_dr?_dont_inherit_lwp test cases fail on
real hardware
lwp_wait(): make the check for deadlock much more permissive.
---
sys/kern/kern_lwp.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/sys/kern/kern_lwp.c b/sys/kern/kern_lwp.c
index 62266a20f66a..dbcb4be52e97 100644
--- a/sys/kern/kern_lwp.c
+++ b/sys/kern/kern_lwp.c
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_lwp.c,v 1.228 2020/02/27 20:52:25 ad Exp $ */
+/* $NetBSD: kern_lwp.c,v 1.229 2020/03/08 17:04:45 ad Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008, 2009, 2019, 2020
@@ -211,7 +211,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.228 2020/02/27 20:52:25 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.229 2020/03/08 17:04:45 ad Exp $");
#include "opt_ddb.h"
#include "opt_lockdebug.h"
@@ -677,12 +677,13 @@ lwp_wait(struct lwp *l, lwpid_t lid, lwpid_t *departed, bool exiting)
}
/*
- * If all other LWPs are waiting for exits or suspends
- * and the supply of zombies and potential zombies is
- * exhausted, then we are about to deadlock.
+ * Break out if the process is exiting, or if all LWPs are
+ * in _lwp_wait(). There are other ways to hang the process
+ * with _lwp_wait(), but the sleep is interruptable so
+ * little point checking for them.
*/
if ((p->p_sflag & PS_WEXIT) != 0 ||
- p->p_nrlwps + p->p_nzlwps - p->p_ndlwps <= p->p_nlwpwait) {
+ p->p_nlwpwait == p->p_nlwps) {
error = EDEADLK;
break;
}