From nobody Sat Sep 27 15:14:01 2025 X-Original-To: dev-commits-src-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4cYrZf31rfz68DNh; Sat, 27 Sep 2025 15:14:02 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R12" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4cYrZd5HzTz44BD; Sat, 27 Sep 2025 15:14:01 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1758986041; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=dwCuF2prOvguHR7JXkLBp8jzXYpBgj/v82+mSakY6MM=; b=q7CPbG/9sXOio6CyewARtQgKoDpyBR03TBjnYM215UrvI3a3h+ORuhhId1yPnWrTZDMNhR JuzMJfUVbPRTRHz/+snk+xKDDVVUg+w7nF/T4uDonzNbYfB6u0stkVLv3kxduUBJm6leEv w+C1k95hmFDTbVKSqAa4l20llVmdU8BTgEAJtq2w4kFhxNO6HABDcDrJbmNIKjlxNTAy5c Ktv6PpN0i65WpMbHItI/XWftFJRnJJEmDS6R0dTpXc0xiEs3cIVKqOCESrMyYBrhEPXWId 9rhNJ7D0//rlUAs+JYXZQqP1Bzz0630lhLNx8rf4m8ftngt2EGQvH806k3TG0w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1758986041; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=dwCuF2prOvguHR7JXkLBp8jzXYpBgj/v82+mSakY6MM=; b=W7Zudj5ufs06Q0bSD7JM8mxkHm/wnITpCxPihbnrwvML8/+p4DLSikXFnxKfiBl8Hpsst/ na0ikFqFqxWBR4X39rCV7wQgS71DZTjAGAPHYuNnwBWujyEaao9jpLinKfUiebn/zrj1E/ QthAqV3KcbGeibO/LBwJ4cuhA7MS3lJJbAqfhM5S5EcCw0V3dvWbCF2kt9LUoVrdC8wGve ChgRU5WljTAk5AKPFOCbfaceg/XZoOHqDgGqfd+7KwnGdEFV2WtlwksMT9Wvs5GrK6Yr7o jxAeV3xvF/YbXf/1QfYXXmmchD1BQ8pDYUb2i1FHKNKMoov8/n2o4hshxxrg4g== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1758986041; a=rsa-sha256; cv=none; b=gpOhnTQ/Iql5vPo4tYVUZ9O69Z30300osuCmej1uyO2qc/o5qkBVL9SMnUYiYuHSvBcYoM 5f+3oQaSUM3DUPNnJHJEUNchicDuERCg31+QoiNpDsFF0sjlkP1cDok+jJZxqf9c6iNuIm ld55NypbAeBlUnOJrRoi5oCDWJwXHbM0S+KUpUZxlXlUl2233klvq9iQkLjRdX+zde0O1r NvOLW/2l35Tq+bEB381C2+EA7CeGyJNgOV3849DhcOya5RI99A2WXsfnaI6bwrzOeE7L++ zg0R5lUnLUa2GBYbH1qMxhxyOkCTGXQdYn2xsdgtJOe042CygQZw/nIy9F2UEw== ARC-Authentication-Results: i=1; mx1.freebsd.org; none Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4cYrZd4t47zfWP; Sat, 27 Sep 2025 15:14:01 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.18.1/8.18.1) with ESMTP id 58RFE1eK083277; Sat, 27 Sep 2025 15:14:01 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 58RFE1TT083274; Sat, 27 Sep 2025 15:14:01 GMT (envelope-from git) Date: Sat, 27 Sep 2025 15:14:01 GMT Message-Id: <202509271514.58RFE1TT083274@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Zhenlei Huang Subject: git: dc32441e3825 - stable/14 - ifnet: Defer detaching address family dependent data List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: zlei X-Git-Repository: src X-Git-Refname: refs/heads/stable/14 X-Git-Reftype: branch X-Git-Commit: dc32441e3825a90027b61259c3c77ef6e213728a Auto-Submitted: auto-generated The branch stable/14 has been updated by zlei: URL: https://cgit.FreeBSD.org/src/commit/?id=dc32441e3825a90027b61259c3c77ef6e213728a commit dc32441e3825a90027b61259c3c77ef6e213728a Author: Zhenlei Huang AuthorDate: 2025-09-03 19:16:40 +0000 Commit: Zhenlei Huang CommitDate: 2025-09-27 15:11:37 +0000 ifnet: Defer detaching address family dependent data While diagnosing PR 279653 and PR 285129, I observed that thread may write to freed memory but the system does not crash. This hides the real problem. A clear NULL pointer derefence is much better than writing to freed memory. PR: 279653 PR: 285129 Reviewed by: glebius MFC after: 3 weeks Differential Revision: https://reviews.freebsd.org/D49444 (cherry picked from commit b5c46895fdddcdb7dd1994598925d6989ea7c8f2) --- sys/net/if.c | 26 +++++++++++++++++++++----- sys/netinet/in.c | 2 ++ sys/netinet6/in6.c | 2 ++ 3 files changed, 25 insertions(+), 5 deletions(-) diff --git a/sys/net/if.c b/sys/net/if.c index f308edd24734..607bcdd2aa80 100644 --- a/sys/net/if.c +++ b/sys/net/if.c @@ -1105,6 +1105,7 @@ if_detach_internal(struct ifnet *ifp, bool vmove) struct ifaddr *ifa; int i; struct domain *dp; + void *if_afdata[AF_MAX]; #ifdef VIMAGE bool shutdown; @@ -1228,15 +1229,30 @@ finish_vnet_shutdown: IF_AFDATA_LOCK(ifp); i = ifp->if_afdata_initialized; ifp->if_afdata_initialized = 0; + if (i != 0) { + /* + * Defer the dom_ifdetach call. + */ + _Static_assert(sizeof(if_afdata) == sizeof(ifp->if_afdata), + "array size mismatch"); + memcpy(if_afdata, ifp->if_afdata, sizeof(if_afdata)); + memset(ifp->if_afdata, 0, sizeof(ifp->if_afdata)); + } IF_AFDATA_UNLOCK(ifp); if (i == 0) return; + /* + * XXXZL: This net epoch wait is not necessary if we have done right. + * But if we do not, at least we can make a guarantee that threads those + * enter net epoch will see NULL address family dependent data, + * e.g. if_afdata[AF_INET6]. A clear NULL pointer derefence is much + * better than writing to freed memory. + */ + NET_EPOCH_WAIT(); SLIST_FOREACH(dp, &domains, 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[dp->dom_family] = NULL; - } + if (dp->dom_ifdetach != NULL && + if_afdata[dp->dom_family] != NULL) + (*dp->dom_ifdetach)(ifp, if_afdata[dp->dom_family]); } } diff --git a/sys/netinet/in.c b/sys/netinet/in.c index 75ff9066875c..857f12a40ce7 100644 --- a/sys/netinet/in.c +++ b/sys/netinet/in.c @@ -1872,6 +1872,8 @@ in_domifdetach(struct ifnet *ifp, void *aux) { struct in_ifinfo *ii = (struct in_ifinfo *)aux; + MPASS(ifp->if_afdata[AF_INET] == NULL); + igmp_domifdetach(ifp); lltable_free(ii->ii_llt); free(ii, M_IFADDR); diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c index b6ecf24a73cd..8d43ae18969a 100644 --- a/sys/netinet6/in6.c +++ b/sys/netinet6/in6.c @@ -2620,6 +2620,8 @@ in6_domifdetach(struct ifnet *ifp, void *aux) { struct in6_ifextra *ext = (struct in6_ifextra *)aux; + MPASS(ifp->if_afdata[AF_INET6] == NULL); + mld_domifdetach(ifp); scope6_ifdetach(ext->scope6_id); nd6_ifdetach(ifp, ext->nd_ifinfo);