Author: ae
Date: Tue Jun 13 10:52:31 2017
New Revision: 319895
URL: https://svnweb.freebsd.org/changeset/base/319895
Log:
Resurrect RTF_RNH_LOCKED flag and restore ability to call rtalloc1_fib()
with acquired RIB lock.
This fixes a possible panic due to trying to acquire RIB rlock when it is
already exclusive locked.
PR: 215963, 215122
MFC after: 1 week
Sponsored by: Yandex LLC
Modified:
head/sys/net/route.c
head/sys/net/route.h
Modified: head/sys/net/route.c
==============================================================================
--- head/sys/net/route.c Tue Jun 13 10:38:28 2017 (r319894)
+++ head/sys/net/route.c Tue Jun 13 10:52:31 2017 (r319895)
@@ -454,18 +454,23 @@ rtalloc1_fib(struct sockaddr *dst, int report, u_long
/*
* Look up the address in the table for that Address Family
*/
- RIB_RLOCK(rh);
+ if ((ignflags & RTF_RNH_LOCKED) == 0)
+ RIB_RLOCK(rh);
+#ifdef INVARIANTS
+ else
+ RIB_LOCK_ASSERT(rh);
+#endif
rn = rh->rnh_matchaddr(dst, &rh->head);
if (rn && ((rn->rn_flags & RNF_ROOT) == 0)) {
newrt = RNTORT(rn);
RT_LOCK(newrt);
RT_ADDREF(newrt);
- RIB_RUNLOCK(rh);
+ if ((ignflags & RTF_RNH_LOCKED) == 0)
+ RIB_RUNLOCK(rh);
return (newrt);
- } else
+ } else if ((ignflags & RTF_RNH_LOCKED) == 0)
RIB_RUNLOCK(rh);
-
/*
* Either we hit the root or could not find any match,
* which basically means: "cannot get there from here".
@@ -748,7 +753,9 @@ ifa_ifwithroute(int flags, const struct sockaddr *dst,
if (ifa == NULL)
ifa = ifa_ifwithnet(gateway, 0, fibnum);
if (ifa == NULL) {
- struct rtentry *rt = rtalloc1_fib(gateway, 0, 0, fibnum);
+ struct rtentry *rt;
+
+ rt = rtalloc1_fib(gateway, 0, flags, fibnum);
if (rt == NULL)
return (NULL);
/*
@@ -1838,8 +1845,13 @@ rtrequest1_fib_change(struct rib_head *rnh, struct rt_
info->rti_info[RTAX_IFP] != NULL ||
(info->rti_info[RTAX_IFA] != NULL &&
!sa_equal(info->rti_info[RTAX_IFA], rt->rt_ifa->ifa_addr))) {
-
+ /*
+ * XXX: Temporarily set RTF_RNH_LOCKED flag in the rti_flags
+ * to avoid rlock in the ifa_ifwithroute().
+ */
+ info->rti_flags |= RTF_RNH_LOCKED;
error = rt_getifa_fib(info, fibnum);
+ info->rti_flags &= ~RTF_RNH_LOCKED;
if (info->rti_ifa != NULL)
free_ifa = 1;
Modified: head/sys/net/route.h
==============================================================================
--- head/sys/net/route.h Tue Jun 13 10:38:28 2017 (r319894)
+++ head/sys/net/route.h Tue Jun 13 10:52:31 2017 (r319895)
@@ -189,7 +189,7 @@ struct rtentry {
/* 0x8000000 and up unassigned */
#define RTF_STICKY 0x10000000 /* always route dst->src */
-#define RTF_RNH_LOCKED 0x40000000 /* unused */
+#define RTF_RNH_LOCKED 0x40000000 /* radix node head is locked */
#define RTF_GWFLAG_COMPAT 0x80000000 /* a compatibility bit for
interacting
with existing routing apps */
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