From 26cfaca81ed1b32467d4c389024030bbb1065cec Mon Sep 17 00:00:00 2001
From: knakahara <knakahara@NetBSD.org>
Date: Thu, 24 Dec 2015 02:27:14 +0000
Subject: [PATCH] fix the following softint parallel operation problem.

(0) softint handler "handler A" is established
(1) CPU#X does softint_schedule() for "handler A"
    - the softhand_t is set SOFTINT_PENDING flag
    - the softhand_t is NOT set SOFTINT_ACTIVE flag yet
(2) CPU#X begins other H/W interrupt processing
(3) CPU#Y does softint_disestablish() for "handler A"
    - waits until softhand_t's SOFTINT_ACTIVE of all CPUs is clear
    - the softhand_t is set not SOFTINT_ACTIVE but SOFTINT_PENDING,
      so CPU#Y does not wait
    - unset the function of "handler A"
(4) CPU#X does softint_execute()
    - the function of "handler A" is already clear, so panic
---
 sys/kern/kern_softint.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sys/kern/kern_softint.c b/sys/kern/kern_softint.c
index 59f383d62417..782540f31639 100644
--- a/sys/kern/kern_softint.c
+++ b/sys/kern/kern_softint.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_softint.c,v 1.41 2014/05/25 15:42:01 rmind Exp $	*/
+/*	$NetBSD: kern_softint.c,v 1.42 2015/12/24 02:27:14 knakahara Exp $	*/
 
 /*-
  * Copyright (c) 2007, 2008 The NetBSD Foundation, Inc.
@@ -170,7 +170,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.41 2014/05/25 15:42:01 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.42 2015/12/24 02:27:14 knakahara Exp $");
 
 #include <sys/param.h>
 #include <sys/proc.h>
@@ -442,8 +442,8 @@ softint_disestablish(void *arg)
 			KASSERT(sh->sh_func != NULL);
 			flags |= sh->sh_flags;
 		}
-		/* Inactive on all CPUs? */
-		if ((flags & SOFTINT_ACTIVE) == 0) {
+		/* Neither pending nor active on all CPUs? */
+		if ((flags & (SOFTINT_PENDING | SOFTINT_ACTIVE)) == 0) {
 			break;
 		}
 		/* Oops, still active.  Wait for it to clear. */