[PATCH net-next] tipc: fix a slab object leak

[PATCH net-next] tipc: fix a slab object leak

[Ying Xue]

When remove TIPC module, there is a warning to remind us that a slab
object is leaked like:

root@localhost:~# rmmod tipc
[   19.056226] =============================================================================
[   19.057549] BUG TIPC (Not tainted): Objects remaining in TIPC on kmem_cache_close()
[   19.058736] -----------------------------------------------------------------------------
[   19.058736]
[   19.060287] INFO: Slab 0xffffea0000519a00 objects=23 used=1 fp=0xffff880014668b00 flags=0x100000000004080
[   19.061915] INFO: Object 0xffff880014668000 @offset=0
[   19.062717] kmem_cache_destroy TIPC: Slab cache still has objects

This is because the listening socket of TIPC topology server is not
closed before TIPC proto handler is unregistered with proto_unregister().
However, as the socket is closed in tipc_exit_net() which is called by
unregister_pernet_subsys() during unregistering TIPC namespace operation,
the warning can be eliminated if calling unregister_pernet_subsys() is
moved before calling proto_unregister().

Fixes: e05b31f4bf89 ("tipc: make tipc socket support net namespace")
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
---
 net/tipc/core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/tipc/core.c b/net/tipc/core.c
index 935205e..be1c9fa 100644
--- a/net/tipc/core.c
+++ b/net/tipc/core.c
@@ -152,11 +152,11 @@ out_netlink:
 static void __exit tipc_exit(void)
 {
 	tipc_bearer_cleanup();
+	unregister_pernet_subsys(&tipc_net_ops);
 	tipc_netlink_stop();
 	tipc_netlink_compat_stop();
 	tipc_socket_stop();
 	tipc_unregister_sysctl();
-	unregister_pernet_subsys(&tipc_net_ops);
 
 	pr_info("Deactivated\n");
 }
-- 
1.7.9.5

Re: [PATCH net-next] tipc: fix a slab object leak

[David Miller]

From: Ying Xue <ying.xue@windriver.com>
Date: Wed, 1 Apr 2015 09:42:50 +0800

> When remove TIPC module, there is a warning to remind us that a slab
> object is leaked like:
> 
> root@localhost:~# rmmod tipc
> [   19.056226] =============================================================================
> [   19.057549] BUG TIPC (Not tainted): Objects remaining in TIPC on kmem_cache_close()
> [   19.058736] -----------------------------------------------------------------------------
> [   19.058736]
> [   19.060287] INFO: Slab 0xffffea0000519a00 objects=23 used=1 fp=0xffff880014668b00 flags=0x100000000004080
> [   19.061915] INFO: Object 0xffff880014668000 @offset=0
> [   19.062717] kmem_cache_destroy TIPC: Slab cache still has objects
> 
> This is because the listening socket of TIPC topology server is not
> closed before TIPC proto handler is unregistered with proto_unregister().
> However, as the socket is closed in tipc_exit_net() which is called by
> unregister_pernet_subsys() during unregistering TIPC namespace operation,
> the warning can be eliminated if calling unregister_pernet_subsys() is
> moved before calling proto_unregister().
> 
> Fixes: e05b31f4bf89 ("tipc: make tipc socket support net namespace")
> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
> Signed-off-by: Ying Xue <ying.xue@windriver.com>

This bug exists in 'net', so that's where I'm applying it.

Can you please target your patches properly, I shouldn't be
doing this kind of work for you.

Re: [PATCH net-next] tipc: fix a slab object leak

[Ying Xue]

On 04/01/2015 11:13 AM, David Miller wrote:
> This bug exists in 'net', so that's where I'm applying it.
> 
> Can you please target your patches properly, I shouldn't be
> doing this kind of work for you.

Sure, I will recreate the patch targeted at "net" tree.

Thanks,
Ying

Re: [PATCH net-next] tipc: fix a slab object leak

[David Miller]

From: Ying Xue <ying.xue@windriver.com>
Date: Wed, 1 Apr 2015 11:16:12 +0800

> On 04/01/2015 11:13 AM, David Miller wrote:
>> This bug exists in 'net', so that's where I'm applying it.
>> 
>> Can you please target your patches properly, I shouldn't be
>> doing this kind of work for you.
> 
> Sure, I will recreate the patch targeted at "net" tree.

I said I applied it, there is nothing for you to do.