diff mbox series

[net-next] net: initialize init_net earlier

Message ID 20220204233809.3082403-1-eric.dumazet@gmail.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [net-next] net: initialize init_net earlier | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5149 this patch: 5149
netdev/cc_maintainers warning 5 maintainers not CCed: rostedt@goodmis.org ahalaney@redhat.com yajun.deng@linux.dev mhiramat@kernel.org akpm@linux-foundation.org
netdev/build_clang success Errors and warnings before: 859 this patch: 859
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 5301 this patch: 5301
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 76 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Feb. 4, 2022, 11:38 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

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")

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 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(-)

Comments

kernel test robot Feb. 5, 2022, 5:52 a.m. UTC | #1 
Hi Eric,

I love your patch! Yet something to improve:

[auto build test ERROR on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Eric-Dumazet/net-initialize-init_net-earlier/20220205-073957
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git c531adaf884d313df2729ca94228317a52e46b83
config: arm-randconfig-r031-20220131 (https://download.01.org/0day-ci/archive/20220205/202202051344.7VoLsgix-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project a73e4ce6a59b01f0e37037761c1e6889d539d233)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://github.com/0day-ci/linux/commit/0d2a51961bd19173f1d7cfa779b9cf82c48e4499
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Eric-Dumazet/net-initialize-init_net-earlier/20220205-073957
        git checkout 0d2a51961bd19173f1d7cfa779b9cf82c48e4499
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from kernel/events/core.c:46:
   In file included from include/linux/filter.h:20:
   In file included from include/linux/if_vlan.h:10:
   In file included from include/linux/netdevice.h:37:
>> include/net/net_namespace.h:519:34: error: non-void function does not return a value [-Werror,-Wreturn-type]
   static inline net_ns_init(void) {}
                                    ^
   1 error generated.
--
   In file included from init/main.c:102:
>> include/net/net_namespace.h:519:34: error: non-void function does not return a value [-Werror,-Wreturn-type]
   static inline net_ns_init(void) {}
                                    ^
   init/main.c:769:20: warning: no previous prototype for function 'arch_post_acpi_subsys_init' [-Wmissing-prototypes]
   void __init __weak arch_post_acpi_subsys_init(void) { }
                      ^
   init/main.c:769:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void __init __weak arch_post_acpi_subsys_init(void) { }
   ^
   static 
   init/main.c:781:20: warning: no previous prototype for function 'mem_encrypt_init' [-Wmissing-prototypes]
   void __init __weak mem_encrypt_init(void) { }
                      ^
   init/main.c:781:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void __init __weak mem_encrypt_init(void) { }
   ^
   static 
   init/main.c:783:20: warning: no previous prototype for function 'poking_init' [-Wmissing-prototypes]
   void __init __weak poking_init(void) { }
                      ^
   init/main.c:783:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void __init __weak poking_init(void) { }
   ^
   static 
   3 warnings and 1 error generated.
--
   kernel/fork.c:162:13: warning: no previous prototype for function 'arch_release_task_struct' [-Wmissing-prototypes]
   void __weak arch_release_task_struct(struct task_struct *tsk)
               ^
   kernel/fork.c:162:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void __weak arch_release_task_struct(struct task_struct *tsk)
   ^
   static 
   kernel/fork.c:764:20: warning: no previous prototype for function 'arch_task_cache_init' [-Wmissing-prototypes]
   void __init __weak arch_task_cache_init(void) { }
                      ^
   kernel/fork.c:764:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void __init __weak arch_task_cache_init(void) { }
   ^
   static 
   kernel/fork.c:859:12: warning: no previous prototype for function 'arch_dup_task_struct' [-Wmissing-prototypes]
   int __weak arch_dup_task_struct(struct task_struct *dst,
              ^
   kernel/fork.c:859:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int __weak arch_dup_task_struct(struct task_struct *dst,
   ^
   static 
   In file included from kernel/fork.c:996:
   In file included from include/linux/init_task.h:18:
>> include/net/net_namespace.h:519:34: error: non-void function does not return a value [-Werror,-Wreturn-type]
   static inline net_ns_init(void) {}
                                    ^
   3 warnings and 1 error generated.
--
   In file included from kernel/kallsyms.c:25:
   In file included from include/linux/filter.h:20:
   In file included from include/linux/if_vlan.h:10:
   In file included from include/linux/netdevice.h:37:
>> include/net/net_namespace.h:519:34: error: non-void function does not return a value [-Werror,-Wreturn-type]
   static inline net_ns_init(void) {}
                                    ^
   kernel/kallsyms.c:587:12: warning: no previous prototype for function 'arch_get_kallsym' [-Wmissing-prototypes]
   int __weak arch_get_kallsym(unsigned int symnum, unsigned long *value,
              ^
   kernel/kallsyms.c:587:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int __weak arch_get_kallsym(unsigned int symnum, unsigned long *value,
   ^
   static 
   1 warning and 1 error generated.
--
   In file included from kernel/sched/core.c:13:
   In file included from kernel/sched/sched.h:49:
   In file included from include/linux/init_task.h:18:
>> include/net/net_namespace.h:519:34: error: non-void function does not return a value [-Werror,-Wreturn-type]
   static inline net_ns_init(void) {}
                                    ^
   kernel/sched/core.c:6401:35: warning: no previous prototype for function 'schedule_user' [-Wmissing-prototypes]
   asmlinkage __visible void __sched schedule_user(void)
                                     ^
   kernel/sched/core.c:6401:22: note: declare 'static' if the function is not intended to be used outside of this translation unit
   asmlinkage __visible void __sched schedule_user(void)
                        ^
                        static 
   1 warning and 1 error generated.
--
   In file included from kernel/sched/fair.c:23:
   In file included from kernel/sched/sched.h:49:
   In file included from include/linux/init_task.h:18:
>> include/net/net_namespace.h:519:34: error: non-void function does not return a value [-Werror,-Wreturn-type]
   static inline net_ns_init(void) {}
                                    ^
   kernel/sched/fair.c:5477:6: warning: no previous prototype for function 'init_cfs_bandwidth' [-Wmissing-prototypes]
   void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
        ^
   kernel/sched/fair.c:5477:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
   ^
   static 
   kernel/sched/fair.c:11703:6: warning: no previous prototype for function 'free_fair_sched_group' [-Wmissing-prototypes]
   void free_fair_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/fair.c:11703:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void free_fair_sched_group(struct task_group *tg) { }
   ^
   static 
   kernel/sched/fair.c:11705:5: warning: no previous prototype for function 'alloc_fair_sched_group' [-Wmissing-prototypes]
   int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
       ^
   kernel/sched/fair.c:11705:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
   ^
   static 
   kernel/sched/fair.c:11710:6: warning: no previous prototype for function 'online_fair_sched_group' [-Wmissing-prototypes]
   void online_fair_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/fair.c:11710:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void online_fair_sched_group(struct task_group *tg) { }
   ^
   static 
   kernel/sched/fair.c:11712:6: warning: no previous prototype for function 'unregister_fair_sched_group' [-Wmissing-prototypes]
   void unregister_fair_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/fair.c:11712:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void unregister_fair_sched_group(struct task_group *tg) { }
   ^
   static 
   5 warnings and 1 error generated.
--
   In file included from kernel/sched/rt.c:6:
   In file included from kernel/sched/sched.h:49:
   In file included from include/linux/init_task.h:18:
>> include/net/net_namespace.h:519:34: error: non-void function does not return a value [-Werror,-Wreturn-type]
   static inline net_ns_init(void) {}
                                    ^
   kernel/sched/rt.c:262:6: warning: no previous prototype for function 'unregister_rt_sched_group' [-Wmissing-prototypes]
   void unregister_rt_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/rt.c:262:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void unregister_rt_sched_group(struct task_group *tg) { }
   ^
   static 
   kernel/sched/rt.c:264:6: warning: no previous prototype for function 'free_rt_sched_group' [-Wmissing-prototypes]
   void free_rt_sched_group(struct task_group *tg) { }
        ^
   kernel/sched/rt.c:264:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void free_rt_sched_group(struct task_group *tg) { }
   ^
   static 
   kernel/sched/rt.c:266:5: warning: no previous prototype for function 'alloc_rt_sched_group' [-Wmissing-prototypes]
   int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
       ^
   kernel/sched/rt.c:266:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
   ^
   static 
   kernel/sched/rt.c:680:6: warning: no previous prototype for function 'sched_rt_bandwidth_account' [-Wmissing-prototypes]
   bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
        ^
   kernel/sched/rt.c:680:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
   ^
   static 
   4 warnings and 1 error generated.


vim +519 include/net/net_namespace.h

   515	
   516	#ifdef CONFIG_NET
   517	void net_ns_init(void);
   518	#else
 > 519	static inline net_ns_init(void) {}
   520	#endif
   521	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 5b61c462e534be468c81d2b0f4ef586b209dd4b8..2ecbd7c11c88e016b1a6a450f07ee2cd94048f62 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 net_ns_init(void) {}
+#endif
+
 #endif /* __NET_NET_NAMESPACE_H */
diff --git a/init/main.c b/init/main.c
index 65fa2e41a9c0904131525d504f3ec86add44f141..ada50f5a15e4397e45b0e5c06bab051b1ce193d9 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 1eaa0b88e3ba5d800484656f2c3420af57050294..f662c6a7d7b49b836a05efc74aeffc7fc9e4e147 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 8711350085d6b55a4f3da19bc69e521f9efb7861..0ec2f5906a27c7f930e832835682d69a32e3c8e1 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;
@@ -1087,7 +1081,7 @@  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;
 
@@ -1108,6 +1102,9 @@  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");
@@ -1122,12 +1119,8 @@  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);