From nobody Wed Sep 3 19:17:25 2025 X-Original-To: dev-commits-src-main@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 4cHC6Y6bHTz660d6; Wed, 03 Sep 2025 19:17:25 +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 4cHC6Y5frxz3TVw; Wed, 03 Sep 2025 19:17:25 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1756927045; 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=/8mACImvWHNR/Xo5oCd2bQ+H0haeps1MRpddzrMIqPY=; b=m6bGnZo9su3mXD1Gt8CYmMG1xNpUUIHstngDZprJ0rXyzVZUXEwJy3Kb/EM2xZhtZdpcAP 1I2IkRLNyT7KapPzpNO4f0ds9W+1u/Wzuhsbrz4akR+BBqMFZ20ObO4pQ8mUrX54xeuoo3 Q6pzGD+OjjYsk6qomJWS3aSQqlXS9pqArNJrW4bKyYzrvbBP5guQox1qc8xxHodl/nGqJX S3nb18OvRRF+N6O2IMDVjbPARzJiDm2z2FnbFcTfap5NeOY3Z/TU7dr9StG1E6F88A+6VL LSl4v9OFLZKY4Tts2SdTrq92vM5BKWUHAa50sP8C55betLfSkDyFyNOEFbB06Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1756927045; 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=/8mACImvWHNR/Xo5oCd2bQ+H0haeps1MRpddzrMIqPY=; b=UgpWOls2i/dJsV3Y4JJvxVtw1gmXIA+7wIQQ0T7uCxPkrAoddrg3B5ob2cAcZsqmS7XTsK DiOQ+3XqzXfP4llEi1yPSt0yvkerSinwpni1OFQTulnmjbWfpKRQcpoA6GQHUkmtIp/OY7 W7MfE9qfI8gzhjTBdYghNu9KpzLwKT1BSakU8ujRer2oSa0nQsmwH8dSK1A/W3AtSV64iR hFs9jZPwJ5rjXwZcEG6PMdkNL5OsigLMgbGkAAp9tde1z6lbjWOc/dMuzgBZBSbYAM3WUN paTgwBwXfuYMbN+iYfXDDwYgc1KHxvIEsWZkwxjWsV27vvUwXkEFCUkmttfQ0g== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1756927045; a=rsa-sha256; cv=none; b=jd/pEfRRk0t9I4DJkpqAVZQuWd5/tlVLOa7K55Vbdyp4Hr3nnUXhBCxyw+pTddaMJUOb8l qv36bvUNGKtgBSr7qFacllYrQttSr/1IiDchmxp+V4GQcac3ibhJzqvFqRTdHtShQ/MTiO mDgm8CfxWvrYEdNsZqpl3A5kPuivqGZWIZPg24tPWGZdIcyj4A3/Obf3nkd5ASkQmL6wH/ Jujwk3XRi0143Od12ObQIWgn6tYRRv97wVNg5kbiuLUTNEkEoMFVSCJbXq6axyrCpInqvS hV3JCVQWPQpDd3wqUON98u5yYbOwcQh8j1hd70kUvLdtCmp0ZqqL+bd9hpqyYQ== 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 4cHC6Y5DSTzTkM; Wed, 03 Sep 2025 19:17:25 +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 583JHPGZ037835; Wed, 3 Sep 2025 19:17:25 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 583JHP2x037832; Wed, 3 Sep 2025 19:17:25 GMT (envelope-from git) Date: Wed, 3 Sep 2025 19:17:25 GMT Message-Id: <202509031917.583JHP2x037832@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Zhenlei Huang Subject: git: b5c46895fddd - main - ifnet: Defer detaching address family dependent data List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@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/main X-Git-Reftype: branch X-Git-Commit: b5c46895fdddcdb7dd1994598925d6989ea7c8f2 Auto-Submitted: auto-generated The branch main has been updated by zlei: URL: https://cgit.FreeBSD.org/src/commit/?id=b5c46895fdddcdb7dd1994598925d6989ea7c8f2 commit b5c46895fdddcdb7dd1994598925d6989ea7c8f2 Author: Zhenlei Huang AuthorDate: 2025-09-03 19:16:40 +0000 Commit: Zhenlei Huang CommitDate: 2025-09-03 19:16:40 +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 --- 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 0fc30488f1e5..b6a798aa0fab 100644 --- a/sys/net/if.c +++ b/sys/net/if.c @@ -1101,6 +1101,7 @@ 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; @@ -1224,15 +1225,30 @@ 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 0e283a7d099d..75ff1f5f3d68 100644 --- a/sys/netinet/in.c +++ b/sys/netinet/in.c @@ -1882,6 +1882,8 @@ 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 a9e6c4eaa51b..be6233d8e4f8 100644 --- a/sys/netinet6/in6.c +++ b/sys/netinet6/in6.c @@ -2618,6 +2618,8 @@ 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);