From patchwork Fri May 10 06:36:03 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wenbin Zeng X-Patchwork-Id: 10938267 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BEABB1390 for ; Fri, 10 May 2019 06:37:25 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B040928C0E for ; Fri, 10 May 2019 06:37:25 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A3E4128C2C; Fri, 10 May 2019 06:37:25 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 581FD28C0E for ; Fri, 10 May 2019 06:37:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726969AbfEJGhN (ORCPT ); Fri, 10 May 2019 02:37:13 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:44810 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726873AbfEJGhN (ORCPT ); Fri, 10 May 2019 02:37:13 -0400 Received: by mail-pf1-f195.google.com with SMTP id g9so2662609pfo.11; Thu, 09 May 2019 23:37:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=tZpDbbxPQIQaiTEJ/QF3eG59ACeQtX21Wr99/jZNM7o=; b=r59rDHqtOd7p+7W9lwVnV5p8DCUR6qGWm1fA+Se52beD9X8hdi5gXvUCA/jU5nhPDl WF3brRF3Y+iKrRQCfzoL7srTYKFWGrF4/+JKPn2GZDDQMP4Y32QZVWgJ8fpzz4JHDC/j UxJliP3I3+QfBu346rmvtNAiw8aEa1KrCRxRBDErVdos5adye4rfGww0oten6Smdy2Cj oRf6DSnhVd+Y6RzhNRsT2Nb/KrQ6xDm+2pd9qCCNTDMNtvZgf8j7kRKGEcMUqsJRXHGV /FycWZVKTUm+USwcg0lSigbRGpnzCfKUYsrXV5HD2U4o1IWUz3kIm9Cr1Z6V51X6yv0X 4HPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=tZpDbbxPQIQaiTEJ/QF3eG59ACeQtX21Wr99/jZNM7o=; b=o8qNj3xgEwnmTliR1dgcmSsIgabDiB48PR/bKu3qYkeqqrP3S7DqY4ekTsZWbtwDaU 3SHTjplOcRo4lp2nOLaMnxafxuMREZRcHfTrvQMK84xJc+rHCyyker/ONZfnuvZEOzOs JgcwslPXGLoWPdGzmlokmrLOKfGVMRrmMnPn/EgOl9ICTaGBJQBSvCkZyVvG89+UHK0w GBoYkgQ+rrJwsulm2tDwuPV5WMeeTwtJSRUHScX+F0RHVaTBgBWqRy9ypCCeeFtFQnu7 xGR1j7qPmPoK87kcH9oZ+xKijpFDya2bDuw/k4m3igXSAcPtkPBkzrTPjU/tDi/pUh+l 4+lw== X-Gm-Message-State: APjAAAVbfGLXmDEeaWxM1ERhu366o6KIDMqeqGS8NpctOzZKVLPH/4qQ cZl0aS7tsDnvthd8m7YpMs8= X-Google-Smtp-Source: APXvYqyTPtOYvxSUX3bbrvCZ4KxRbJM8QDJZj2fhpRLkLZL3C4WBC0szcESYnw8qQPdTbioxaatmIw== X-Received: by 2002:a63:2124:: with SMTP id h36mr11608289pgh.186.1557470232308; Thu, 09 May 2019 23:37:12 -0700 (PDT) Received: from bridge.localdomain ([119.28.31.106]) by smtp.gmail.com with ESMTPSA id v6sm4469263pgi.88.2019.05.09.23.37.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 09 May 2019 23:37:11 -0700 (PDT) From: Wenbin Zeng X-Google-Original-From: Wenbin Zeng To: bfields@fieldses.org, viro@zeniv.linux.org.uk, davem@davemloft.net Cc: jlayton@kernel.org, trond.myklebust@hammerspace.com, anna.schumaker@netapp.com, wenbinzeng@tencent.com, dsahern@gmail.com, nicolas.dichtel@6wind.com, willy@infradead.org, edumazet@google.com, jakub.kicinski@netronome.com, tyhicks@canonical.com, chuck.lever@oracle.com, neilb@suse.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-nfs@vger.kernel.org Subject: [PATCH v2 3/3] auth_gss: fix deadlock that blocks rpcsec_gss_exit_net when use-gss-proxy==1 Date: Fri, 10 May 2019 14:36:03 +0800 Message-Id: <1557470163-30071-4-git-send-email-wenbinzeng@tencent.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1557470163-30071-1-git-send-email-wenbinzeng@tencent.com> References: <1556692945-3996-1-git-send-email-wenbinzeng@tencent.com> <1557470163-30071-1-git-send-email-wenbinzeng@tencent.com> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When use-gss-proxy is set to 1, write_gssp() creates a rpc client in gssp_rpc_create(), this increases netns refcount by 2, these refcounts are supposed to be released in rpcsec_gss_exit_net(), but it will never happen because rpcsec_gss_exit_net() is triggered only when netns refcount gets to 0, specifically: refcount=0 -> cleanup_net() -> ops_exit_list -> rpcsec_gss_exit_net It is a deadlock situation here, refcount will never get to 0 unless rpcsec_gss_exit_net() is called. This fix introduced a new callback i.e. evict in struct proc_ns_operations, which is called in nsfs_evict. Moving rpcsec_gss_exit_net to evict path gives it a chance to get called and avoids the above deadlock situation. Signed-off-by: Wenbin Zeng --- net/sunrpc/auth_gss/auth_gss.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c index 3fd56c0..3e6bd59 100644 --- a/net/sunrpc/auth_gss/auth_gss.c +++ b/net/sunrpc/auth_gss/auth_gss.c @@ -2136,14 +2136,17 @@ static __net_init int rpcsec_gss_init_net(struct net *net) return gss_svc_init_net(net); } -static __net_exit void rpcsec_gss_exit_net(struct net *net) +static void rpcsec_gss_evict_net(struct net *net) { - gss_svc_shutdown_net(net); + struct sunrpc_net *sn = net_generic(net, sunrpc_net_id); + + if (sn->gssp_clnt) + gss_svc_shutdown_net(net); } static struct pernet_operations rpcsec_gss_net_ops = { .init = rpcsec_gss_init_net, - .exit = rpcsec_gss_exit_net, + .evict = rpcsec_gss_evict_net, }; /*