Date: Wed, 25 Feb 2009 11:18:18 +0000 (UTC) From: Robert Watson <rwatson@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org Subject: svn commit: r189029 - stable/7/sys/net Message-ID: <200902251118.n1PBIIcQ094668@svn.freebsd.org>
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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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