From c10ffe988f15a0306d5d8cb1c6b475c9fe2fc2c9 Mon Sep 17 00:00:00 2001 From: Roman Mashak Date: Fri, 24 Feb 2017 11:00:32 -0500 Subject: [PATCH] net sched actions: decrement module reference count after table flush. [ 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 % Fixes: f97017cdefef ("net-sched: Fix actions flushing") Signed-off-by: Roman Mashak Signed-off-by: Jamal Hadi Salim Acked-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/act_api.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 06e7c4a37245..694a06f1e0d5 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -820,10 +820,8 @@ static int tca_action_flush(struct net *net, struct nlattr *nla, 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 *net, struct nlattr *nla, out_module_put: module_put(a.ops->owner); err_out: -noflush_out: kfree_skb(skb); return err; } -- 2.20.1