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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 D9609C31E47 for ; Wed, 12 Jun 2019 12:10:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF2AC20866 for ; Wed, 12 Jun 2019 12:10:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hitdsLAI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406370AbfFLMKV (ORCPT ); Wed, 12 Jun 2019 08:10:21 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:37251 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404957AbfFLMKV (ORCPT ); Wed, 12 Jun 2019 08:10:21 -0400 Received: by mail-pl1-f196.google.com with SMTP id bh12so6566022plb.4; Wed, 12 Jun 2019 05:10:20 -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=FzWj9Xhuon5QpbEDoeMtLzky5+/Bs1gO2JVhXGS69rU=; b=hitdsLAIBJmCOqstVgzBYk7T/tw9Q9CjJnmRkfiU0fRcNOclTQA0fUJ32GxtmOIKCk yahfx1aIuASn849H8h4SCbWAQxWnjHWPixtuoM0gsAZl8JIFeeGSu5iMieRnT2GLS5uc vPvjrpKtytCGE2zLTjhEkUKaVgEIcCKB8f22x+Fj7msnv7TJyXbV5IGtbclNkByxKxV6 NUAtXtTuquSezIzdHPWM67b7UPpNY1AYOhSYwlV0KwNqIQPSQ7OkdhVD1GmTs1jlNuox TfAIK/22wiKDoTF9YVspEhfFCJFFjFX9EEnJxRD8p6Uy8pzjTQCiP7BU4aVP46MJGW3r w1sQ== 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=FzWj9Xhuon5QpbEDoeMtLzky5+/Bs1gO2JVhXGS69rU=; b=Hg0IezoKvp8ne/sFqmvHHP2p3HPiY7yi7LI1d/ctbSAoQxDMJ8vNTnqAOq0UEzLHWf 8TWPktbnjfvfwc6zSMNjgTWT8pAPKfi7JFJgzVdEvR1wPJELpR3VhqnMGMf5chnBUZan kpURWjFc4YrCHDrxTq61FxpNwDnjMNZbwf12/QZ4Dc2NBYDI2cpcinJYiZvpc7jB/nDx 52YUk+xW8BMXfXvvZhhv5obPgzbb/l6VL29+2ELQu5dbQa+/ivX9kvwxfgDCw4wv1BXh 542p2XHR3dr5XIvaVm1RpQblSWvncir3iYRYGHagz1YVENMhWBaVQe7fWFTfaWtdiiEh lk1Q== X-Gm-Message-State: APjAAAWD7MyL1JBZ+khBU69gpJxX28xHGhR6hOYIpqF+u4kVWnrroQjf JKV6CezVB80AxHejz7nap3IXO0Lo3Ug= X-Google-Smtp-Source: APXvYqzoj3tzZ+XGMPpbzQlbGEDBYK866FfUXZZy3+TZnqIKBMniNjaG+z4EySHYOcpy7rRUQqCR3A== X-Received: by 2002:a17:902:b102:: with SMTP id q2mr71770682plr.149.1560341420193; Wed, 12 Jun 2019 05:10:20 -0700 (PDT) Received: from bridge.tencent.com ([119.28.31.106]) by smtp.gmail.com with ESMTPSA id s5sm5035653pji.9.2019.06.12.05.10.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 Jun 2019 05:10:19 -0700 (PDT) From: Wenbin Zeng X-Google-Original-From: Wenbin Zeng To: bfields@fieldses.org, davem@davemloft.net, viro@zeniv.linux.org.uk 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 v3 0/3] auth_gss: netns refcount leaks when use-gss-proxy==1 Date: Wed, 12 Jun 2019 20:09:27 +0800 Message-Id: <1560341370-24197-1-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 This patch series fixes an auth_gss bug that results in netns refcount leaks when use-gss-proxy is set to 1. The problem was found in privileged docker containers with gssproxy service enabled and /proc/net/rpc/use-gss-proxy set to 1, the corresponding struct net->count ends up at 2 after container gets killed, the consequence is that the struct net cannot be freed. It turns out that write_gssp() called gssp_rpc_create() to create a rpc client, this increases net->count by 2; rpcsec_gss_exit_net() is supposed to decrease net->count but it never gets called because its call-path is: net->count==0 -> cleanup_net -> ops_exit_list -> rpcsec_gss_exit_net Before rpcsec_gss_exit_net() gets called, net->count cannot reach 0, this is a deadlock situation. To fix the problem, we must break the deadlock, rpcsec_gss_exit_net() should move out of the put() path and find another chance to get called, I think nsfs_evict() is a good place to go, when netns inode gets evicted we call rpcsec_gss_exit_net() to free the rpc client, this requires a new callback i.e. evict to be added in struct proc_ns_operations, and add netns_evict() as one of netns_operations as well. v1->v2: * in nsfs_evict(), move ->evict() in front of ->put() v2->v3: * rpcsec_gss_evict_net() directly call gss_svc_shutdown_net() regardless if gssp_clnt is null, this is exactly same to what rpcsec_gss_exit_net() previously did Wenbin Zeng (3): nsfs: add evict callback into struct proc_ns_operations netns: add netns_evict into netns_operations auth_gss: fix deadlock that blocks rpcsec_gss_exit_net when use-gss-proxy==1 fs/nsfs.c | 2 ++ include/linux/proc_ns.h | 1 + include/net/net_namespace.h | 1 + net/core/net_namespace.c | 12 ++++++++++++ net/sunrpc/auth_gss/auth_gss.c | 4 ++-- 5 files changed, 18 insertions(+), 2 deletions(-) -- 1.8.3.1