Re: [PATCH net] ipvs: fix WARNING in __ip_vs_cleanup_batch()

On 2022/10/31 18:35, Julian Anastasov wrote:
> 
> 	Hello,
> 
> On Mon, 31 Oct 2022, Zhengchao Shao wrote:
> 
>> During the initialization of ip_vs_conn_net_init(), if file ip_vs_conn
>> or ip_vs_conn_sync fails to be created, the initialization is successful
>> by default. Therefore, the ip_vs_conn or ip_vs_conn_sync file doesn't
>> be found during the remove.
>>
>> The following is the stack information:
>> name 'ip_vs_conn_sync'
>> WARNING: CPU: 3 PID: 9 at fs/proc/generic.c:712
>> remove_proc_entry+0x389/0x460
>> Modules linked in:
>> Workqueue: netns cleanup_net
>> RIP: 0010:remove_proc_entry+0x389/0x460
>> Call Trace:
>> <TASK>
>> __ip_vs_cleanup_batch+0x7d/0x120
>> ops_exit_list+0x125/0x170
>> cleanup_net+0x4ea/0xb00
>> process_one_work+0x9bf/0x1710
>> worker_thread+0x665/0x1080
>> kthread+0x2e4/0x3a0
>> ret_from_fork+0x1f/0x30
>> </TASK>
>>
>> Fixes: 61b1ab4583e2 ("IPVS: netns, add basic init per netns.")
>> Signed-off-by: Zhengchao Shao <[email protected]>
>> ---
>>   net/netfilter/ipvs/ip_vs_conn.c | 20 +++++++++++++++-----
>>   1 file changed, 15 insertions(+), 5 deletions(-)
>>
>> diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
>> index 8c04bb57dd6f..b126bd7df321 100644
>> --- a/net/netfilter/ipvs/ip_vs_conn.c
>> +++ b/net/netfilter/ipvs/ip_vs_conn.c
>> @@ -1447,12 +1447,22 @@ int __net_init ip_vs_conn_net_init(struct netns_ipvs *ipvs)
>>   {
>>   	atomic_set(&ipvs->conn_count, 0);
>>   
>> -	proc_create_net("ip_vs_conn", 0, ipvs->net->proc_net,
>> -			&ip_vs_conn_seq_ops, sizeof(struct ip_vs_iter_state));
>> -	proc_create_net("ip_vs_conn_sync", 0, ipvs->net->proc_net,
>> -			&ip_vs_conn_sync_seq_ops,
>> -			sizeof(struct ip_vs_iter_state));
>> +	if (!proc_create_net("ip_vs_conn", 0, ipvs->net->proc_net,
>> +			     &ip_vs_conn_seq_ops,
>> +			     sizeof(struct ip_vs_iter_state)))
>> +		goto err_conn;
>> +
>> +	if (!proc_create_net("ip_vs_conn_sync", 0, ipvs->net->proc_net,
>> +			     &ip_vs_conn_sync_seq_ops,
>> +			     sizeof(struct ip_vs_iter_state)))
>> +		goto err_conn_sync;
>> +
>>   	return 0;
>> +
>> +err_conn_sync:
>> +	remove_proc_entry("ip_vs_conn", ipvs->net->proc_net);
>> +err_conn:
>> +	return -ENOMEM;
>>   }
>>   
>>   void __net_exit ip_vs_conn_net_cleanup(struct netns_ipvs *ipvs)
>> -- 
>> 2.17.1
> 
> 	Good catch. But can you add some #ifdef CONFIG_PROC_FS
> as done in commit 4bc3c8dc9f5f ("ipvs: fix possible memory leak in
> ip_vs_control_net_init") ? You can also extend it to include
> ifdefs and ENOMEM in ip_vs_app.c:ip_vs_app_net_init(). If you
> prefer, it can be a separate patch.
> 
> Regards
> 
> --
> Julian Anastasov <[email protected]>
> 

Hi Anastasov:
	Thank you for your reply. I'd like to do it, and I will
send them in v2.

Zhengchao Shao
>