[src/netbsd-6-0]: src/sys/kern Pull up following revision(s) (requested by kn...

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

details:   https://anonhg.NetBSD.org/src/rev/5cc134f90d14
branches:  netbsd-6-0
changeset: 775134:5cc134f90d14
user:      snj <snj%NetBSD.org@localhost>
date:      Thu Jul 14 06:43:35 2016 +0000

description:
Pull up following revision(s) (requested by knakahara in ticket #1356):
        sys/kern/kern_softint.c: revision 1.42
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

diffstat:

 sys/kern/kern_softint.c |  8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diffs (29 lines):

diff -r 3a5d42d42c7e -r 5cc134f90d14 sys/kern/kern_softint.c
--- a/sys/kern/kern_softint.c   Wed May 18 10:44:41 2016 +0000
+++ b/sys/kern/kern_softint.c   Thu Jul 14 06:43:35 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_softint.c,v 1.38.14.1 2013/02/08 19:31:19 riz Exp $       */
+/*     $NetBSD: kern_softint.c,v 1.38.14.2 2016/07/14 06:43:35 snj Exp $       */
 
 /*-
  * Copyright (c) 2007, 2008 The NetBSD Foundation, Inc.
@@ -176,7 +176,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.38.14.1 2013/02/08 19:31:19 riz Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.38.14.2 2016/07/14 06:43:35 snj Exp $");
 
 #include <sys/param.h>
 #include <sys/proc.h>
@@ -424,8 +424,8 @@
                        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. */