net: initialize init_net earlier
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>
diff --git a/init/main.c b/init/main.c
index 65fa2e4..ada50f5 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();
