Date: Sun, 11 Apr 2010 11:51:45 +0000 (UTC) From: "Bjoern A. Zeeb" <bz@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r206470 - head/sys/net Message-ID: <201004111151.o3BBpjlJ088724@svn.freebsd.org>
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Author: bz Date: Sun Apr 11 11:51:44 2010 New Revision: 206470 URL: http://svn.freebsd.org/changeset/base/206470 Log: In if_detach_internal() we cannot hold the af_data lock over the dom_ifdetach() calls as they might sleep for callout_drain(). Do as we do in if_attachdomain1() [r121470] and handle if_afdata_initialized earlier and call dom_ifdetach() unlocked. Discussed with: rwatson MFC after: 10 days Modified: head/sys/net/if.c Modified: head/sys/net/if.c ============================================================================== --- head/sys/net/if.c Sun Apr 11 11:49:24 2010 (r206469) +++ head/sys/net/if.c Sun Apr 11 11:51:44 2010 (r206470) @@ -897,14 +897,20 @@ if_detach_internal(struct ifnet *ifp, in devctl_notify("IFNET", ifp->if_xname, "DETACH", NULL); if_delgroups(ifp); + /* + * We cannot hold the lock over dom_ifdetach calls as they might + * sleep, for example trying to drain a callout, thus open up the + * theoretical race with re-attaching. + */ IF_AFDATA_LOCK(ifp); - for (dp = domains; ifp->if_afdata_initialized > 0 && dp; dp = dp->dom_next) { + i = ifp->if_afdata_initialized; + ifp->if_afdata_initialized = 0; + IF_AFDATA_UNLOCK(ifp); + for (dp = domains; i > 0 && dp; dp = dp->dom_next) { if (dp->dom_ifdetach && ifp->if_afdata[dp->dom_family]) (*dp->dom_ifdetach)(ifp, ifp->if_afdata[dp->dom_family]); } - ifp->if_afdata_initialized = 0; - IF_AFDATA_UNLOCK(ifp); } #ifdef VIMAGE
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