Module Name: src
Committed By: ozaki-r
Date: Thu Jan 25 03:09:05 UTC 2018
Modified Files:
src/sys/net: rtsock.c
Log Message:
Fix another deadlock
When waiting for a route update to finish, a waiter has to release its reference
to the route to avoid a deadlock. Because a updater tries to wait for references
to a target route (except for a reference by the updater itself) to be released.
To generate a diff of this commit:
cvs rdiff -u -r1.237 -r1.238 src/sys/net/rtsock.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/net/rtsock.c
diff -u src/sys/net/rtsock.c:1.237 src/sys/net/rtsock.c:1.238
--- src/sys/net/rtsock.c:1.237 Fri Jan 19 05:19:29 2018
+++ src/sys/net/rtsock.c Thu Jan 25 03:09:05 2018
@@ -1,4 +1,4 @@
-/* $NetBSD: rtsock.c,v 1.237 2018/01/19 05:19:29 ozaki-r Exp $ */
+/* $NetBSD: rtsock.c,v 1.238 2018/01/25 03:09:05 ozaki-r Exp $ */
/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -61,7 +61,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rtsock.c,v 1.237 2018/01/19 05:19:29 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rtsock.c,v 1.238 2018/01/25 03:09:05 ozaki-r Exp $");
#ifdef _KERNEL_OPT
#include "opt_inet.h"
@@ -1015,11 +1015,21 @@ COMPATNAME(route_output)(struct mbuf *m,
* Release rt_so_mtx to avoid a deadlock with route_intr
* and also serialize updating routes to avoid another.
*/
+ if (rt_updating) {
+ /* Release to allow the updater to proceed */
+ rt_unref(rt);
+ rt = NULL;
+ }
while (rt_updating) {
error = cv_wait_sig(&rt_update_cv, rt_so_mtx);
if (error != 0)
goto flush;
}
+ if (rt == NULL) {
+ error = rtrequest1(RTM_GET, &info, &rt);
+ if (error != 0)
+ goto flush;
+ }
rt_updating = true;
mutex_exit(rt_so_mtx);
