Patch "net sched actions: decrement module reference count after table flush." has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

net sched actions: decrement module reference count after table flush.

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
net-sched-actions-decrement-module-reference-count-after-table-flush.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Roman Mashak <[email protected]>
Date: Fri, 24 Feb 2017 11:00:32 -0500
Subject: net sched actions: decrement module reference count after table flush.

From: Roman Mashak <[email protected]>

[ Upstream commit edb9d1bff4bbe19b8ae0e71b1f38732591a9eeb2 ]

When tc actions are loaded as a module and no actions have been installed, flushing them would result in actions removed from the memory, but modules reference count not being decremented, so that the modules would not be unloaded.

Following is example with GACT action:

% sudo modprobe act_gact
% lsmod
Module Size Used by
act_gact 16384 0
%
% sudo tc actions ls action gact
%
% sudo tc actions flush action gact
% lsmod
Module Size Used by
act_gact 16384 1
% sudo tc actions flush action gact
% lsmod
Module Size Used by
act_gact 16384 2
% sudo rmmod act_gact
rmmod: ERROR: Module act_gact is in use
....

After the fix:
% lsmod
Module Size Used by
act_gact 16384 0
%
% sudo tc actions add action pass index 1
% sudo tc actions add action pass index 2
% sudo tc actions add action pass index 3
% lsmod
Module Size Used by
act_gact 16384 3
%
% sudo tc actions flush action gact
% lsmod
Module Size Used by
act_gact 16384 0
%
% sudo tc actions flush action gact
% lsmod
Module Size Used by
act_gact 16384 0
% sudo rmmod act_gact
% lsmod
Module Size Used by
%

---
 net/sched/act_api.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

@@ -820,10 +820,8 @@ static int tca_action_flush(struct net *
 		goto out_module_put;
 
 	err = a.ops->walk(skb, &dcb, RTM_DELACTION, &a);
-	if (err < 0)
+	if (err <= 0)
 		goto out_module_put;
-	if (err == 0)
-		goto noflush_out;
 
 	nla_nest_end(skb, nest);
 

@@ -840,7 +838,6 @@ static int tca_action_flush(struct net *
 out_module_put:
 	module_put(a.ops->owner);
 err_out:
-noflush_out:
 	kfree_skb(skb);
 	return err;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/net-sched-actions-decrement-module-reference-count-after-table-flush.patch