Date: Tue, 27 Nov 2018 19:40:07 +0000 (UTC) From: Eric van Gyzen <vangyzen@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r341086 - stable/12/sys/netinet6 Message-ID: <201811271940.wARJe7i2032487@repo.freebsd.org>
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Author: vangyzen Date: Tue Nov 27 19:40:07 2018 New Revision: 341086 URL: https://svnweb.freebsd.org/changeset/base/341086 Log: MFC r340257 in6_ifattach_linklocal: handle immediate removal of the new LLA If another thread immediately removes the link-local address added by in6_update_ifa(), in6ifa_ifpforlinklocal() can return NULL, so the following assertion (or dereference) is wrong. Remove the assertion, and handle NULL somewhat better than panicking. This matches all of the other callers of in6_update_ifa(). PR: 219250 Reviewed by: bz, dab (both an earlier version) Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D17898 Modified: stable/12/sys/netinet6/in6_ifattach.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/netinet6/in6_ifattach.c ============================================================================== --- stable/12/sys/netinet6/in6_ifattach.c Tue Nov 27 17:58:25 2018 (r341085) +++ stable/12/sys/netinet6/in6_ifattach.c Tue Nov 27 19:40:07 2018 (r341086) @@ -481,9 +481,16 @@ in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet return (-1); } - ia = in6ifa_ifpforlinklocal(ifp, 0); /* ia must not be NULL */ - KASSERT(ia != NULL, ("%s: ia == NULL, ifp=%p", __func__, ifp)); - + ia = in6ifa_ifpforlinklocal(ifp, 0); + if (ia == NULL) { + /* + * Another thread removed the address that we just added. + * This should be rare, but it happens. + */ + nd6log((LOG_NOTICE, "%s: %s: new link-local address " + "disappeared\n", __func__, if_name(ifp))); + return (-1); + } ifa_free(&ia->ia_ifa); /*
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