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From: Sasha Levin <sashal@kernel•org>
To: linux-kernel@vger•kernel.org, stable@vger•kernel.org
Cc: Eric Dumazet <edumazet@google•com>,
	"David S . Miller" <davem@davemloft•net>,
	Sasha Levin <sashal@kernel•org>,
	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, valentin.schneider@arm•com,
	peterz@infradead•org, 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 5.17 046/149] net: initialize init_net earlier
Date: Fri,  1 Apr 2022 10:23:53 -0400	[thread overview]
Message-ID: <20220401142536.1948161-46-sashal@kernel.org> (raw)
In-Reply-To: <20220401142536.1948161-1-sashal@kernel.org>

From: Eric Dumazet <edumazet@google•com>

[ 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 <edumazet@google•com>
Signed-off-by: David S. Miller <davem@davemloft•net>
Signed-off-by: Sasha Levin <sashal@kernel•org>
---
 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 5b61c462e534..374cc7b260fc 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -513,4 +513,10 @@ 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 65fa2e41a9c0..ada50f5a15e4 100644
--- a/init/main.c
+++ b/init/main.c
@@ -99,6 +99,7 @@
 #include <linux/kcsan.h>
 #include <linux/init_syscalls.h>
 #include <linux/stackdepot.h>
+#include <net/net_namespace.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>
@@ -1116,6 +1117,7 @@ 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 1baab07820f6..91cf709c98b3 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10732,8 +10732,7 @@ 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 a5b5bb99c644..212e65add951 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;
@@ -1084,7 +1078,7 @@ 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;
 
@@ -1105,6 +1099,9 @@ 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");
@@ -1119,12 +1116,8 @@ 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


  parent reply	other threads:[~2022-04-01 14:30 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20220401142536.1948161-1-sashal@kernel.org>
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 002/149] Bluetooth: hci_sync: Fix compilation warning Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 003/149] ath5k: fix OOB in ath5k_eeprom_read_pcal_info_5111 Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 004/149] Bluetooth: fix null ptr deref on hci_sync_conn_complete_evt Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 009/149] Bluetooth: hci_event: Ignore multiple conn complete events Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 017/149] ptp: replace snprintf with sysfs_emit Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 018/149] Bluetooth: hci_sync: Fix queuing commands when HCI_UNREGISTER is set Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 019/149] selftests, xsk: Fix bpf_res cleanup test Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 020/149] net/mlx5e: TC, Hold sample_attr on stack instead of pointer Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 025/149] mlxsw: spectrum: Guard against invalid local ports Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 029/149] ath11k: fix kernel panic during unload/load ath11k modules Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 030/149] ath11k: pci: fix crash on suspend if board file is not found Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 031/149] ath11k: mhi: use mhi_sync_power_up() Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 032/149] net/smc: Send directly when TCP_CORK is cleared Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 034/149] bpf: Make dst_port field in struct bpf_sock 16-bit wide Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 039/149] mt76: mt7921: fix crash when startup fails Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 040/149] mt76: dma: initialize skip_unmap in mt76_dma_rx_fill Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 041/149] i40e: Add sending commands in atomic context Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 042/149] cfg80211: don't add non transmitted BSS to 6GHz scanned channels Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 043/149] libbpf: Fix build issue with llvm-readelf Sasha Levin
2022-04-01 14:23 ` [PATCH AUTOSEL 5.17 044/149] ipv6: make mc_forwarding atomic Sasha Levin
2022-04-01 14:23 ` Sasha Levin [this message]
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 060/149] libbpf: Fix accessing syscall arguments on powerpc Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 061/149] libbpf: Fix accessing the first syscall argument on arm64 Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 062/149] libbpf: Fix accessing the first syscall argument on s390 Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 064/149] tcp: Don't acquire inet_listen_hashbucket::lock with disabled BH Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 074/149] net/mlx5e: Disable TX queues before registering the netdev Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 078/149] iwlwifi: mvm: Correctly set fragmented EBS Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 079/149] iwlwifi: mvm: Passively scan non PSC channels only when requested so Sasha Levin
2022-04-01 14:52   ` Ben Greear
2022-04-09 14:04     ` Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 080/149] iwlwifi: fix small doc mistake for iwl_fw_ini_addr_val Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 081/149] iwlwifi: mvm: move only to an enabled channel Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 082/149] ipv6: annotate some data-races around sk->sk_prot Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 085/149] rtw89: fix RCU usage in rtw89_core_txq_push() Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 086/149] ath11k: Fix frames flush failure caused by deadlock Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 087/149] ipv4: Invalidate neighbour for broadcast address upon address addition Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 088/149] rtw88: change rtw_info() to proper message level Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 099/149] mt76: mt7915: fix injected MPDU transmission to not use HW A-MSDU Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 101/149] mctp: make __mctp_dev_get() take a refcount hold Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 103/149] mt76: mt7615: Fix assigning negative values to unsigned variable Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 109/149] net/smc: correct settings of RMB window update limit Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 111/149] iavf: stop leaking iavf_status as "errno" values Sasha Levin
2022-04-01 14:24 ` [PATCH AUTOSEL 5.17 112/149] macvtap: advertise link netns via netlink Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 114/149] tuntap: add sanity checks about msg_controllen in sendmsg Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 117/149] Bluetooth: Fix not checking for valid hdev on bt_dev_{info,warn,err,dbg} Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 118/149] Bluetooth: use memset avoid memory leaks Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 119/149] bnxt_en: Eliminate unintended link toggle during FW reset Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 123/149] powerpc/64e: Tie PPC_BOOK3E_64 to PPC_FSL_BOOK3E Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 127/149] can: isotp: set default value for N_As to 50 micro seconds Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 128/149] can: etas_es58x: es58x_fd_rx_event_msg(): initialize rx_event_msg before calling es58x_check_msg_len() Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 130/149] net: account alternate interface name memory Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 131/149] net: limit altnames to 64k total Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 132/149] net/mlx5e: Remove overzealous validations in netlink EEPROM query Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 135/149] net: sfp: add 2500base-X quirk for Lantech SFP module Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 138/149] mt76: fix monitor mode crash with sdio driver Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 140/149] iwlwifi: mei: fix building iwlmei Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 142/149] Bluetooth: Fix use after free in hci_send_acl Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 143/149] netfilter: conntrack: revisit gc autotuning Sasha Levin
2022-04-01 14:25 ` [PATCH AUTOSEL 5.17 144/149] netlabel: fix out-of-bounds memory accesses Sasha Levin

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