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tipc: switch order of device registration to fix a crash

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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: a62fbccecd ("tipc: make subscriber server support net namespace")
Signed-off-by: Junwei Hu <hujunwei4@huawei.com>
Reported-by: Wang Wang <wangwang2@huawei.com>
Reviewed-by: Xiaogang Wang <wangxiaogang3@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Junwei Hu 2019-05-16 10:51:15 +08:00 committed by David S. Miller
parent 61fb0d0168
commit 7e27e8d613
1 changed files with 7 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
net/tipc/core.c
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@ -131,10 +131,6 @@ 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;
@ -143,6 +139,10 @@ 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;
@ -150,12 +150,12 @@ 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();
@ -167,10 +167,10 @@ 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");