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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 417FBC433F5 for ; Fri, 1 Apr 2022 14:50:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348365AbiDAOv7 (ORCPT ); Fri, 1 Apr 2022 10:51:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348913AbiDAOpE (ORCPT ); Fri, 1 Apr 2022 10:45:04 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F7552976F7; Fri, 1 Apr 2022 07:35:08 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2CAA260AC0; Fri, 1 Apr 2022 14:34:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C8A5AC340EE; Fri, 1 Apr 2022 14:34:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648823671; bh=vuXQ7peP/W4Eg3nMz7d/M5/lb3ur9UE13yD5yISQwts=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BHN5llHtLmatntVYQx/mQb07YXYELGv9CB9ASYeKTGQuBrP2TtuvVXDwYAwWk1g3l VbR1eSilWCHAmdQJfNruwHCiXntnY0X3MEhEij6v2Sl1sJqe8643pIS7mPHKnrTIiE sH1ceKu8ESzvbuqQvXNOTm/AoZHeiVhpv9wzZ6n8FYJdveAbxkOkJamqauNx07tfW5 TXXiRDEssZfZm+JIpLgmwYizlCC4Q4Q6cHj+6/XeXceODJsf4WPNW2EUn9ReeN/50m /nzwl6OGSsxXmBssKTjovKYrw9X39qtt0g50iSIlX6L5bWEtQVPHNLySFb0V9MRlOY KaWkWCB0sjJxg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Eric Dumazet , "David S . Miller" , Sasha Levin , kuba@kernel.org, pabeni@redhat.com, akpm@linux-foundation.org, mhiramat@kernel.org, rostedt@goodmis.org, vbabka@suse.cz, ahalaney@redhat.com, wangkefeng.wang@huawei.com, linux@rasmusvillemoes.dk, keescook@chromium.org, mark-pk.tsai@mediatek.com, peterz@infradead.org, valentin.schneider@arm.com, bigeasy@linutronix.de, toke@redhat.com, imagedong@tencent.com, petrm@nvidia.com, memxor@gmail.com, arnd@arndb.de, changbin.du@intel.com, yajun.deng@linux.dev, hmukos@yandex-team.ru, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.16 034/109] net: initialize init_net earlier Date: Fri, 1 Apr 2022 10:31:41 -0400 Message-Id: <20220401143256.1950537-34-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220401143256.1950537-1-sashal@kernel.org> References: <20220401143256.1950537-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Dumazet [ Upstream commit 9c1be1935fb68b2413796cdc03d019b8cf35ab51 ] While testing a patch that will follow later ("net: add netns refcount tracker to struct nsproxy") I found that devtmpfs_init() was called before init_net was initialized. This is a bug, because devtmpfs_setup() calls ksys_unshare(CLONE_NEWNS); This has the effect of increasing init_net refcount, which will be later overwritten to 1, as part of setup_net(&init_net) We had too many prior patches [1] trying to work around the root cause. Really, make sure init_net is in BSS section, and that net_ns_init() is called earlier at boot time. Note that another patch ("vfs: add netns refcount tracker to struct fs_context") also will need net_ns_init() being called before vfs_caches_init() As a bonus, this patch saves around 4KB in .data section. [1] f8c46cb39079 ("netns: do not call pernet ops for not yet set up init_net namespace") b5082df8019a ("net: Initialise init_net.count to 1") 734b65417b24 ("net: Statically initialize init_net.dev_base_head") v2: fixed a build error reported by kernel build bots (CONFIG_NET=n) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/net/net_namespace.h | 6 ++++++ init/main.c | 2 ++ net/core/dev.c | 3 +-- net/core/net_namespace.c | 17 +++++------------ 4 files changed, 14 insertions(+), 14 deletions(-) diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index bb5fa5914032..2ba326f9e004 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -479,4 +479,10 @@ static inline void fnhe_genid_bump(struct net *net) atomic_inc(&net->fnhe_genid); } +#ifdef CONFIG_NET +void net_ns_init(void); +#else +static inline void net_ns_init(void) {} +#endif + #endif /* __NET_NET_NAMESPACE_H */ diff --git a/init/main.c b/init/main.c index bb984ed79de0..cb68bc48a682 100644 --- a/init/main.c +++ b/init/main.c @@ -99,6 +99,7 @@ #include #include #include +#include #include #include @@ -1113,6 +1114,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void) key_init(); security_init(); dbg_late_init(); + net_ns_init(); vfs_caches_init(); pagecache_init(); signals_init(); diff --git a/net/core/dev.c b/net/core/dev.c index 2078d04c6482..8c47e0f2075d 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -11403,8 +11403,7 @@ static int __net_init netdev_init(struct net *net) BUILD_BUG_ON(GRO_HASH_BUCKETS > 8 * sizeof_field(struct napi_struct, gro_bitmask)); - if (net != &init_net) - INIT_LIST_HEAD(&net->dev_base_head); + INIT_LIST_HEAD(&net->dev_base_head); net->dev_name_head = netdev_create_hash(); if (net->dev_name_head == NULL) diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 9702d2b0d920..9745cb6fdf51 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -44,13 +44,7 @@ EXPORT_SYMBOL_GPL(net_rwsem); static struct key_tag init_net_key_domain = { .usage = REFCOUNT_INIT(1) }; #endif -struct net init_net = { - .ns.count = REFCOUNT_INIT(1), - .dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head), -#ifdef CONFIG_KEYS - .key_domain = &init_net_key_domain, -#endif -}; +struct net init_net; EXPORT_SYMBOL(init_net); static bool init_net_initialized; @@ -1081,7 +1075,7 @@ static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid, rtnl_set_sk_err(net, RTNLGRP_NSID, err); } -static int __init net_ns_init(void) +void __init net_ns_init(void) { struct net_generic *ng; @@ -1102,6 +1096,9 @@ static int __init net_ns_init(void) rcu_assign_pointer(init_net.gen, ng); +#ifdef CONFIG_KEYS + init_net.key_domain = &init_net_key_domain; +#endif down_write(&pernet_ops_rwsem); if (setup_net(&init_net, &init_user_ns)) panic("Could not setup the initial network namespace"); @@ -1116,12 +1113,8 @@ static int __init net_ns_init(void) RTNL_FLAG_DOIT_UNLOCKED); rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid, RTNL_FLAG_DOIT_UNLOCKED); - - return 0; } -pure_initcall(net_ns_init); - static void free_exit_list(struct pernet_operations *ops, struct list_head *net_exit_list) { ops_pre_exit_list(ops, net_exit_list); -- 2.34.1