The following reply was made to PR kern/149804; it has been noted by GNATS.
From: dfil...@freebsd.org (dfilter service) To: bug-follo...@freebsd.org Cc: Subject: Re: kern/149804: commit references a PR Date: Mon, 27 Sep 2010 19:27:05 +0000 (UTC) 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; } _______________________________________________ svn-src-...@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org" _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
