git: 810fe03349df - stable/13 - init: fix shutdown race

From: Corvin Köhne <corvink_at_FreeBSD.org>
Date: Tue, 06 Dec 2022 14:42:17 UTC
The branch stable/13 has been updated by corvink:

URL: https://cgit.FreeBSD.org/src/commit/?id=810fe03349df4d4deb3eb59baa76075f2d3f5514

commit 810fe03349df4d4deb3eb59baa76075f2d3f5514
Author:     Corvin Köhne <CorvinK@beckhoff.com>
AuthorDate: 2022-09-06 07:06:51 +0000
Commit:     Corvin Köhne <corvink@FreeBSD.org>
CommitDate: 2022-12-06 14:41:34 +0000

    init: fix shutdown race
    
    When calling shutdown, shutdown sends a signal to init and exits. This
    causes a race condition for the waitpid function. If the signal wins the
    race, wpid will be set to -1 and init calls death_single. If shutdown
    wins the race, wpid will be set to the pid of the shutdown process and
    the requested_transition will be ignored.
    
    Reviewed by:            imp
    Differential Revision:  https://reviews.freebsd.org/D36356
    MFC after:              1 week
    Sponsored by:           Beckhoff Automation GmbH & Co. KG
    
    (cherry picked from commit 203f2c14c4b3c7a3e8f51a5a248201e1eb091886)
---
 sbin/init/init.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sbin/init/init.c b/sbin/init/init.c
index 230c141bd351..3e53da6b99a7 100644
--- a/sbin/init/init.c
+++ b/sbin/init/init.c
@@ -1138,10 +1138,10 @@ run_script(const char *script)
 	do {
 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
 			collect_child(wpid);
+		if (requested_transition == death_single ||
+		    requested_transition == reroot)
+			return (state_func_t) requested_transition;
 		if (wpid == -1) {
-			if (requested_transition == death_single ||
-			    requested_transition == reroot)
-				return (state_func_t) requested_transition;
 			if (errno == EINTR)
 				continue;
 			warning("wait for %s on %s failed: %m; going to "