Author: delphij
Date: Mon Oct 11 11:25:37 2010
New Revision: 213687
URL: http://svn.freebsd.org/changeset/base/213687
Log:
MFC r213225:
Add a bandaid for a long-standing race condition during route entry
un-expiring.
The previous version of code have no locking when testing rt_refcnt.
The result of the lack of locking may result in a condition where
a routing entry have a reference count but at the same time have
RTPRF_OURS bit set and an expiration timer. These would eventually
lead to a panic:
panic: rtqkill route really not free
When the system have ICMP redirects accepted from local gateway
in a moderate frequency, for instance.
Commit this workaround for now until we have some better solution.
PR: kern/149804
Reviewed by: bz
Tested by: Zhao Xin, Pete French
Modified:
stable/8/sys/netinet/in_rmx.c
stable/8/sys/netinet6/in6_rmx.c
Directory Properties:
stable/8/sys/ (props changed)
stable/8/sys/amd64/include/xen/ (props changed)
stable/8/sys/cddl/contrib/opensolaris/ (props changed)
stable/8/sys/contrib/dev/acpica/ (props changed)
stable/8/sys/contrib/pf/ (props changed)
stable/8/sys/dev/xen/xenpci/ (props changed)
Changes in other areas also in this revision:
Modified:
stable/7/sys/netinet/in_rmx.c
stable/7/sys/netinet6/in6_rmx.c
Directory Properties:
stable/7/sys/ (props changed)
stable/7/sys/cddl/contrib/opensolaris/ (props changed)
stable/7/sys/contrib/dev/acpica/ (props changed)
stable/7/sys/contrib/pf/ (props changed)
Modified: stable/8/sys/netinet/in_rmx.c
==============================================================================
--- stable/8/sys/netinet/in_rmx.c Mon Oct 11 09:42:30 2010
(r213686)
+++ stable/8/sys/netinet/in_rmx.c Mon Oct 11 11:25:37 2010
(r213687)
@@ -121,12 +121,13 @@ in_matroute(void *v_arg, struct radix_no
struct radix_node *rn = rn_match(v_arg, head);
struct rtentry *rt = (struct rtentry *)rn;
- /*XXX locking? */
- if (rt && rt->rt_refcnt == 0) { /* this is first reference */
+ if (rt) {
+ RT_LOCK(rt);
if (rt->rt_flags & RTPRF_OURS) {
rt->rt_flags &= ~RTPRF_OURS;
rt->rt_rmx.rmx_expire = 0;
}
+ RT_UNLOCK(rt);
}
return rn;
}
Modified: stable/8/sys/netinet6/in6_rmx.c
==============================================================================
--- stable/8/sys/netinet6/in6_rmx.c Mon Oct 11 09:42:30 2010
(r213686)
+++ stable/8/sys/netinet6/in6_rmx.c Mon Oct 11 11:25:37 2010
(r213687)
@@ -193,11 +193,13 @@ in6_matroute(void *v_arg, struct radix_n
struct radix_node *rn = rn_match(v_arg, head);
struct rtentry *rt = (struct rtentry *)rn;
- if (rt && rt->rt_refcnt == 0) { /* this is first reference */
+ if (rt) {
+ RT_LOCK(rt);
if (rt->rt_flags & RTPRF_OURS) {
rt->rt_flags &= ~RTPRF_OURS;
rt->rt_rmx.rmx_expire = 0;
}
+ RT_UNLOCK(rt);
}
return rn;
}
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