Commit 9d2a8fa9 authored Mar 21, 2011 by Eric W. Biederman Committed by David S. Miller Mar 21, 2011

net ipv6: Fix duplicate /proc/sys/net/ipv6/neigh directory entries.

When I was fixing issues with unregisgtering tables under /proc/sys/net/ipv6/neigh
by adding a mount point it appears I missed a critical ordering issue, in the
ipv6 initialization. I had not realized that ipv6_sysctl_register is called
at the very end of the ipv6 initialization and in particular after we call
neigh_sysctl_register from ndisc_init.

"neigh" needs to be initialized in ipv6_static_sysctl_register which is
the first ipv6 table to initialized, and definitely before ndisc_init.
This removes the weirdness of duplicate tables while still providing a
"neigh" mount point which prevents races in sysctl unregistering.

This was initially reported at https://bugzilla.kernel.org/show_bug.cgi?id=31232

Reported-by: <sunkan@zappa.cx>
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent d5cd9244

net/ipv6/sysctl_net_ipv6.c

+11 −7

Original line number	Diff line number	Diff line
		@@ -17,6 +17,16 @@

		static struct ctl_table empty[1];

		static ctl_table ipv6_static_skeleton[] = {
		{
		.procname = "neigh",
		.maxlen = 0,
		.mode = 0555,
		.child = empty,
		},
		{ }
		};

		static ctl_table ipv6_table_template[] = {
		{
		.procname = "route",
		@@ -37,12 +47,6 @@ static ctl_table ipv6_table_template[] = {
		.mode = 0644,
		.proc_handler = proc_dointvec
		},
		{
		.procname = "neigh",
		.maxlen = 0,
		.mode = 0555,
		.child = empty,
		},
		{ }
		};

		@@ -160,7 +164,7 @@ static struct ctl_table_header *ip6_base;

		int ipv6_static_sysctl_register(void)
		{
		ip6_base = register_sysctl_paths(net_ipv6_ctl_path, empty);
		ip6_base = register_sysctl_paths(net_ipv6_ctl_path, ipv6_static_skeleton);
		if (ip6_base == NULL)
		return -ENOMEM;
		return 0;