From nobody Sun May 07 23:52:03 2023 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 4QF1Rm0X7bz49k92; Sun, 7 May 2023 23:52:04 +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 "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4QF1Rl74ZPz3v75; Sun, 7 May 2023 23:52:03 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1683503524; 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=DJWA12kiud4skPPgnRbUU4HkaDKCOlC46pHRX8+alVQ=; b=L2768W40U/TZh/NITVdS+FkhUEZG/TZIt8v8aSbD648YQTocLwEl2882SNchRdMAt7BHrx mxWR9LXlS5JqEqx+TP91+75RlMRf6eE+hudqDWvmyCgGnreXGVwDmhSzfIsEPRnHCYGied utFdH41n4ym6b5S8NtO6cie6d2NA0CjViyD3gBWBV3aPyFPcX8IU91xzj/eWywCEK7rwGF f44ptTVdnmWZMsWe9c9Afp6idb94F4Nv5GVJxk0o5wIQTv7yOgwsrbXcGy7V9LiZGSHpgv 82fAOYEO/PXFC+FyngQ7JfJOSEzt28qUc1Zh+/WT0xVoczTiZKy8isFgecG6OA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1683503524; 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=DJWA12kiud4skPPgnRbUU4HkaDKCOlC46pHRX8+alVQ=; b=F6PQDBcNUkCdue23FpmRva/vDIBHYrKoFoQjmRtVRL+lbzHvxkX8yZVb2+RjNmdyAugc5K cVE4n+4U6cRuwYoOkBo4PYQPF7qorI+0ECjDDZTU6uUplUtT7IUzjMWe5MxNgAPDIIVOb4 VrnM62HiDyOdk7ypilCXP30ZW8vrNjtGXp7eR20MaSOeP28J/3z5rxIlCJp9yj7m+T97tM 00LQDG0tVg5cs0mA0NPOvqjmlkIkcB5zZ3ISmNKSVpB6g88IwBujGP24gcxCoQtYgs9WMC shAXJXWsoGRKUiMMqngEuzC8ziTz7gchbvevdZ86VsBPXKhJGGvBFOHBbm2Q7A== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1683503524; a=rsa-sha256; cv=none; b=tlBW0eUeJL8e3CcrIInWdk5PIRp0ZMna6+OyU7RTArb3HMYTZqh920jonoQXSMReJTqi81 WfZNo1VlRKSk7n5buOBgBc25q3WBd1b13kCddRHI8VNQXZW9FZW3Qx4tHpi0WX6iRcs3Pe 0gBNNgJcwv177Osy6DnboJn1Q7iu47rL0+vhLgXgVp76UNG+shrC1EOCcBhK3kHSwVMJzy 4nMV/APp6shNMDJgnk14b+vvp+3eQbVaKDtYJM+EZ8sAz72lO5llUV5trWNWezbkIobJSi dvRPJi54D9WE5YaAZr09Rbj8YRuhrdiSkM/XNCpIsDr+vdR6YCx0mwgBN0cD8A== 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 4QF1Rl5txRzdv6; Sun, 7 May 2023 23:52:03 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 347Nq3si004397; Sun, 7 May 2023 23:52:03 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 347Nq3sH004385; Sun, 7 May 2023 23:52:03 GMT (envelope-from git) Date: Sun, 7 May 2023 23:52:03 GMT Message-Id: <202305072352.347Nq3sH004385@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: "Jason A. Harmening" Subject: git: 0745d837c2e9 - main - unionfs: prevent upperrootvp from being recycled during mount 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: Sender: owner-dev-commits-src-all@freebsd.org X-BeenThere: dev-commits-src-all@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: jah X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 0745d837c2e9e37bd069bd7c05c8f9892fba0752 Auto-Submitted: auto-generated X-ThisMailContainsUnwantedMimeParts: N The branch main has been updated by jah: URL: https://cgit.FreeBSD.org/src/commit/?id=0745d837c2e9e37bd069bd7c05c8f9892fba0752 commit 0745d837c2e9e37bd069bd7c05c8f9892fba0752 Author: Jason A. Harmening AuthorDate: 2023-03-26 01:41:33 +0000 Commit: Jason A. Harmening CommitDate: 2023-05-07 23:30:43 +0000 unionfs: prevent upperrootvp from being recycled during mount If upperrootvp is doomed by a concurrent unmount, unionfs_nodeget() may return without a reference or lock on it. unionfs_domount() must prevent the vnode from being recycled for use by a different file until it is finished with the vnode, namely once vfs_register_upper_from_vp() fails. Accomplish this by holding the reference returned by namei() a bit longer. Reviewed by: kib, markj Tested by: pho Differential Revision: https://reviews.freebsd.org/D39767 --- sys/fs/unionfs/union_vfsops.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/sys/fs/unionfs/union_vfsops.c b/sys/fs/unionfs/union_vfsops.c index 8831397c8c5b..cd6c7bd90655 100644 --- a/sys/fs/unionfs/union_vfsops.c +++ b/sys/fs/unionfs/union_vfsops.c @@ -285,8 +285,8 @@ unionfs_domount(struct mount *mp) */ error = unionfs_nodeget(mp, ump->um_uppervp, ump->um_lowervp, NULLVP, &(ump->um_rootvp), NULL); - vrele(upperrootvp); if (error != 0) { + vrele(upperrootvp); free(ump, M_UNIONFSMNT); mp->mnt_data = NULL; return (error); @@ -295,11 +295,24 @@ unionfs_domount(struct mount *mp) KASSERT((ump->um_rootvp->v_vflag & VV_ROOT) != 0, ("%s: rootvp without VV_ROOT", __func__)); + /* + * Do not release the namei() reference on upperrootvp until after + * we attempt to register the upper mounts. A concurrent unmount + * of the upper or lower FS may have caused unionfs_nodeget() to + * create a unionfs node with a NULL upper or lower vp and with + * no reference held on upperrootvp or lowerrootvp. + * vfs_register_upper() should subsequently fail, which is what + * we want, but we must ensure neither underlying vnode can be + * reused until that happens. We assume the caller holds a reference + * to lowerrootvp as it is the mount's covered vnode. + */ lowermp = vfs_register_upper_from_vp(ump->um_lowervp, mp, &ump->um_lower_link); uppermp = vfs_register_upper_from_vp(ump->um_uppervp, mp, &ump->um_upper_link); + vrele(upperrootvp); + if (lowermp == NULL || uppermp == NULL) { if (lowermp != NULL) vfs_unregister_upper(lowermp, &ump->um_lower_link);