Commit 4f747a79 authored by Junwei Hu's avatar Junwei Hu Committed by Greg Kroah-Hartman

tipc: switch order of device registration to fix a crash

[ Upstream commit 7e27e8d6 ]

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 92166190
......@@ -129,10 +129,6 @@ 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;
......@@ -141,6 +137,10 @@ 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;
......@@ -148,12 +148,12 @@ 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();
......@@ -165,10 +165,10 @@ 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");
......
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