[Devel] [patch 06/20] [Network namespace] Move the nsproxy NULL affection

[Daniel Lezcano]

Dmitry Mishin wrote:
> On Monday 11 December 2006 00:58, dlezcano at fr.ibm.com wrote:
>> Signed-off-by: Daniel Lezcano <dlezcano at fr.ibm.com>
>>
>> ---
>>
>>  kernel/nsproxy.c |    2 +-
>>  1 files changed, 1 insertion(+), 1 deletion(-)
>>
>> Index: 2.6.19-rc6-mm2/kernel/nsproxy.c
>> ===================================================================
>> --- 2.6.19-rc6-mm2.orig/kernel/nsproxy.c
>> +++ 2.6.19-rc6-mm2/kernel/nsproxy.c
>> @@ -54,10 +54,10 @@ void exit_task_namespaces(struct task_st
>>  {
>>  	struct nsproxy *ns = p->nsproxy;
>>  	if (ns) {
>> +		put_nsproxy(ns);
>>  		task_lock(p);
>>  		p->nsproxy = NULL;
>>  		task_unlock(p);
>> -		put_nsproxy(ns);
>>  	}
>>  }
> This will follow in a race.

Yep.

I did that to have a quick fix for the net_ns cleanup.
The problem raised is the p->nsproxy = NULL followed by put_ns_proxy and 
put_net_ns. This one will call free_net_ns followed by ip_fib_cleanup 
and that will use current_net_ns (which is current->nsproxy->net_ns) 
with nsproxy = NULL

I think, the right fix is to have ip_fib_cleanup called with the net_ns 
pointer as parameter and in this case current_net_ns needs to be checked 
in all the code to ensure it will not be used by the cleanup.


_______________________________________________
Containers mailing list
Containers at lists.osdl.org
https://lists.osdl.org/mailman/listinfo/containers