From: Junwei Hu hujunwei4@huawei.com
[ 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: a62fbccecd62 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/tipc/core.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
--- a/net/tipc/core.c +++ b/net/tipc/core.c @@ -126,10 +126,6 @@ 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; @@ -138,6 +134,10 @@ 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; @@ -145,12 +145,12 @@ 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(); @@ -162,10 +162,10 @@ out_netlink: 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");