From owner-svn-src-head@FreeBSD.ORG Mon Sep 27 19:26:57 2010 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0AC4E106566B; Mon, 27 Sep 2010 19:26:57 +0000 (UTC) (envelope-from delphij@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id D39E48FC08; Mon, 27 Sep 2010 19:26:56 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id o8RJQu2O047374; Mon, 27 Sep 2010 19:26:56 GMT (envelope-from delphij@svn.freebsd.org) Received: (from delphij@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id o8RJQuHE047371; Mon, 27 Sep 2010 19:26:56 GMT (envelope-from delphij@svn.freebsd.org) Message-Id: <201009271926.o8RJQuHE047371@svn.freebsd.org> From: Xin LI Date: Mon, 27 Sep 2010 19:26:56 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r213225 - in head/sys: netinet netinet6 X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Sep 2010 19:26:57 -0000 Author: delphij Date: Mon Sep 27 19:26:56 2010 New Revision: 213225 URL: http://svn.freebsd.org/changeset/base/213225 Log: 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 MFC after: 2 weeks Modified: head/sys/netinet/in_rmx.c head/sys/netinet6/in6_rmx.c Modified: head/sys/netinet/in_rmx.c ============================================================================== --- head/sys/netinet/in_rmx.c Mon Sep 27 19:03:18 2010 (r213224) +++ head/sys/netinet/in_rmx.c Mon Sep 27 19:26:56 2010 (r213225) @@ -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: head/sys/netinet6/in6_rmx.c ============================================================================== --- head/sys/netinet6/in6_rmx.c Mon Sep 27 19:03:18 2010 (r213224) +++ head/sys/netinet6/in6_rmx.c Mon Sep 27 19:26:56 2010 (r213225) @@ -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; }