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=-2.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 EC87DC04A6B for ; Fri, 10 May 2019 06:36:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BDC65217D6 for ; Fri, 10 May 2019 06:36:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qw5fJbIG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727000AbfEJGgz (ORCPT ); Fri, 10 May 2019 02:36:55 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:44296 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726983AbfEJGgz (ORCPT ); Fri, 10 May 2019 02:36:55 -0400 Received: by mail-pg1-f195.google.com with SMTP id z16so2495969pgv.11; Thu, 09 May 2019 23:36:55 -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=vT8J+5xe8+a83KFHodncMBgwSSqGKELQF/J0hFsWGtA=; b=qw5fJbIGPWcA28KqHaWQHU/4N2mlSVKQW5V8JZ3jxW1bmtyoGCRFuE54VT++XfaTJk ECxfJP3LMFFdmQKpmVSMTUFPSj7EQEhyrpUmvoWn/JXvQhhTXtoIPmM7IVQnrvIX4sGC luQbTA0HnLqWm4CZGiDjuLFIht94D1/x4evanFtBzUyXK3HUy10849a4P5DDwa+tUzMm DoYdzXrW0LGwGe+Jqc5v7SWv9BHbuNCuFUEYQwMhetftF7i5eySCSCclPrmkA4t0cNpI kbUsdwY722an5VqZDnc9t9W0IB87r2MsZAstjN8j1nZ1EE/0htDpUiHwk4gyh8iio2s3 U9WQ== 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=vT8J+5xe8+a83KFHodncMBgwSSqGKELQF/J0hFsWGtA=; b=JfQNZkXFzQutdtHDMWk2DIE0YH9/Yf5EC7v/NpxJ9aZLr9y8SCUyeNSkcBiPfkhEBJ PZHInS0c/3y87g81XcK0mvOYliNBrVro/9yYlivT/DJQo6CCB6IzTOS8wZL5+s8bky8Z qkw+WL/NmiVGXnB0VCKrP5kunyN62CAqLw0LnvN7C3tJXHnYyp73XfMToX44DRdoLtcy N5P6HoeX4m8jpg57OhFC/w+owCiUMAmeoBWMiLxdz0FTtb90thFOdXIEW0YjOEpsjM9M nsXJeLfusjv6Zs0PvacVLwdphMIBON/RumLMFj/hujnFCgTBS77PIhm2G8cupymF0z6+ jqiA== X-Gm-Message-State: APjAAAVFU77qHIgHL+fyu5KS+6kmlbDQJaj7B1iW/c1z6H0KG+IkaRYJ UroImobV1RWP3nTsh7O/DRo= X-Google-Smtp-Source: APXvYqwSCNBXHSW4DyU7xEdjpK+/gp7Kt1cZx3ZbTpDXuFDJYS90bWQTn34/E72UI3GXTtUvVjOxaQ== X-Received: by 2002:aa7:9109:: with SMTP id 9mr11557887pfh.244.1557470214902; Thu, 09 May 2019 23:36:54 -0700 (PDT) Received: from bridge.localdomain ([119.28.31.106]) by smtp.gmail.com with ESMTPSA id v6sm4469263pgi.88.2019.05.09.23.36.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 09 May 2019 23:36:54 -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 0/3] auth_gss: netns refcount leaks when use-gss-proxy==1 Date: Fri, 10 May 2019 14:36:00 +0800 Message-Id: <1557470163-30071-1-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() 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 | 9 ++++++--- 5 files changed, 22 insertions(+), 3 deletions(-) -- 1.8.3.1