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Commit a336df52 authored by Junwei Hu's avatar Junwei Hu Committed by Greg Kroah-Hartman
Browse files

tipc: switch order of device registration to fix a crash 



[ Upstream commit 7e27e8d6130c5e88fac9ddec4249f7f2337fe7f8 ]

When tipc is loaded while many processes try to create a TIPC socket,
a crash occurs:
 PANIC: Unable to handle kernel paging request at virtual
 address "dfff20000000021d"
 pc : tipc_sk_create+0x374/0x1180 [tipc]
 lr : tipc_sk_create+0x374/0x1180 [tipc]
   Exception class = DABT (current EL), IL = 32 bits
 Call trace:
  tipc_sk_create+0x374/0x1180 [tipc]
  __sock_create+0x1cc/0x408
  __sys_socket+0xec/0x1f0
  __arm64_sys_socket+0x74/0xa8
 ...

This is due to race between sock_create and unfinished
register_pernet_device. tipc_sk_insert tries to do
"net_generic(net, tipc_net_id)".
but tipc_net_id is not initialized yet.

So switch the order of the two to close the race.

This can be reproduced with multiple processes doing socket(AF_TIPC, ...)
and one process doing module removal.

Fixes: a62fbcce ("tipc: make subscriber server support net namespace")
Signed-off-by: default avatarJunwei Hu <hujunwei4@huawei.com>
Reported-by: default avatarWang Wang <wangwang2@huawei.com>
Reviewed-by: default avatarXiaogang Wang <wangxiaogang3@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent dcdc0a49

net/tipc/core.c

+7 −7
Original line number Diff line number Diff line
@@ -125,10 +125,6 @@ static int __init tipc_init(void) 
	if (err)

		goto out_netlink_compat;



	err = tipc_socket_init();

	if (err)

		goto out_socket;



	err = tipc_register_sysctl();

	if (err)

		goto out_sysctl;
@@ -137,6 +133,10 @@ static int __init tipc_init(void) 
	if (err)

		goto out_pernet;



	err = tipc_socket_init();

	if (err)

		goto out_socket;



	err = tipc_bearer_setup();

	if (err)

		goto out_bearer;
@@ -144,12 +144,12 @@ static int __init tipc_init(void) 
	pr_info("Started in single node mode\n");

	return 0;

out_bearer:

	tipc_socket_stop();

out_socket:

	unregister_pernet_subsys(&tipc_net_ops);

out_pernet:

	tipc_unregister_sysctl();

out_sysctl:

	tipc_socket_stop();

out_socket:

	tipc_netlink_compat_stop();

out_netlink_compat:

	tipc_netlink_stop();
@@ -161,10 +161,10 @@ static int __init tipc_init(void) 
static void __exit tipc_exit(void)

{

	tipc_bearer_cleanup();

	tipc_socket_stop();

	unregister_pernet_subsys(&tipc_net_ops);

	tipc_netlink_stop();

	tipc_netlink_compat_stop();

	tipc_socket_stop();

	tipc_unregister_sysctl();



	pr_info("Deactivated\n");