Author: rwatson
Date: Wed Feb 25 11:18:18 2009
New Revision: 189029
URL: http://svn.freebsd.org/changeset/base/189029
Log:
Correct a deadlock and a rtentry leak in rt_check():
- In the event that a gateway route has to be looked up, drop the lock
on 'rt' before reacquiring it 'rt0' in order to avoid deadlock.
- In the event the original route has evaporated or is no longer up
after the gateway route lookup, call RTFREE() on the gateway route
before retrying.
This is a potential errata candidate patch.
PR: kern/130652
Submitted by: Dmitrij Tejblum <tejblum at yandex-team.ru>
Reviewed by: bz
Tested by: Pete French <petefrench at ticketswitch.com>
Modified:
stable/7/sys/net/route.c
Modified: stable/7/sys/net/route.c
==============================================================================
--- stable/7/sys/net/route.c Wed Feb 25 11:13:13 2009 (r189028)
+++ stable/7/sys/net/route.c Wed Feb 25 11:18:18 2009 (r189029)
@@ -1650,27 +1650,34 @@ retry:
return (ENETUNREACH);
}
/*
- * Relock it and lose the added reference.
- * All sorts of things could have happenned while we
- * had no lock on it, so check for them.
+ * Relock it and lose the added reference. All sorts
+ * of things could have happenned while we had no
+ * lock on it, so check for them. rt need to be
+ * unlocked to avoid possible deadlock.
*/
+ RT_UNLOCK(rt);
RT_RELOCK(rt0);
- if (rt0 == NULL || ((rt0->rt_flags & RTF_UP) == 0))
+ if (rt0 == NULL || ((rt0->rt_flags & RTF_UP) == 0)) {
/* Ru-roh.. what we had is no longer any good */
+ RTFREE(rt);
goto retry;
+ }
/*
* While we were away, someone replaced the gateway.
* Since a reference count is involved we can't just
* overwrite it.
*/
if (rt0->rt_gwroute) {
- if (rt0->rt_gwroute != rt) {
- RTFREE_LOCKED(rt);
- goto retry;
- }
+ if (rt0->rt_gwroute != rt)
+ RTFREE(rt);
} else {
rt0->rt_gwroute = rt;
}
+ /*
+ * Since rt was not locked, we need recheck that
+ * it still may be used (e.g. up)
+ */
+ goto retry;
}
RT_LOCK_ASSERT(rt);
RT_UNLOCK(rt0);
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