From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9864BC43219 for ; Wed, 1 May 2019 06:43:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6901520651 for ; Wed, 1 May 2019 06:43:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="VICxe5gW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725973AbfEAGn1 (ORCPT ); Wed, 1 May 2019 02:43:27 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:46138 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725776AbfEAGn0 (ORCPT ); Wed, 1 May 2019 02:43:26 -0400 Received: by mail-pl1-f195.google.com with SMTP id bi2so3051403plb.13; Tue, 30 Apr 2019 23:43:26 -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=VICxe5gWrDbyG3fzdiTZ3NxrsnDGD2Bmk3eV/dfKI+Nspwr3svro/9NsjGbukA37YM EreicPwuqGiQxyidBPdvRKLT7UQfIfoemCx1oFnRwJmgDXOH9m3jGoWaEDppqsqI7TR8 mNNiNLCyLJJB33DoeIodvbZpuDgVtvsuJuId4/lwVaT2uwiGL1P1ZwOmj1jPk9/dkjqv h6CIZ77DVLxmeCJBc7LOVLMKA0fg1VPl17ujhbBvxBArg1+onpwQuv2B/8BS4W09FJmk PL3XIKlZN5Ua49e0i03pz6qg3690Zqu4IdzHr9qx0NkTU4L9FYx8RuFRDnDvgiwpB/HF gs0w== 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=rUXYhCTHwn82yeucOjRE3EkxUho6vIlw3r5CdXCJXx1M2sOnsBePG2BeFJfsNwgf5/ xI/WqZRKYDNLae90tDBTc9CvPXE66yo4ZRNZuzVGTb4LtoGWxc7lGJed8rMdIp87z07w tDu7ZdjyLQCFxPW0gbtyHjJjWJjX8muOSE583imK9/yEoaH0L3IK047zgBH17p4gc+wt 62bGGnhtlsrzYrZ76KdEj83V0T5S7tfCPNqZ192aTfTtWmmsoiItxYkngdMc+6+yM872 2eTIqvjNhmezt6nX7IZ5EdHZH7NnZXTHkzQqC0MLvNFAI0VEe61yLS6SJMOKZuxYsty3 KXYQ== X-Gm-Message-State: APjAAAVtOniobu8idukFvI51Gz4zUl2Ifo72SHsn9/GR2LwI5Nrcv8U9 sfZ0OUmhtTyJ8vYhvumwkEE= X-Google-Smtp-Source: APXvYqyCkaw2Mtev/GQI2Ae/9T0TBTMQyOtHtcJP5lPKRujliHcQCSg+hLV/y0BUYpsPOA4Ju4SE5g== X-Received: by 2002:a17:902:6b47:: with SMTP id g7mr28995601plt.227.1556693005762; Tue, 30 Apr 2019 23:43:25 -0700 (PDT) Received: from bridge.localdomain ([119.28.31.106]) by smtp.gmail.com with ESMTPSA id 25sm56800323pfo.145.2019.04.30.23.43.22 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Apr 2019 23:43:25 -0700 (PDT) From: Wenbin Zeng X-Google-Original-From: Wenbin Zeng To: viro@zeniv.linux.org.uk, davem@davemloft.net, bfields@fieldses.org, 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 Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-nfs@vger.kernel.org Subject: [PATCH 3/3] auth_gss: fix deadlock that blocks rpcsec_gss_exit_net when use-gss-proxy==1 Date: Wed, 1 May 2019 14:42:25 +0800 Message-Id: <1556692945-3996-4-git-send-email-wenbinzeng@tencent.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1556692945-3996-1-git-send-email-wenbinzeng@tencent.com> References: <1556692945-3996-1-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 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, }; /* -- 1.8.3.1