From: Roman Mashak <mrv@xxxxxxxxxxxx> commit edb9d1bff4bbe19b8ae0e71b1f38732591a9eeb2 upstream. 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 <mrv@xxxxxxxxxxxx> Signed-off-by: Jamal Hadi Salim <jhs@xxxxxxxxxxxx> Acked-by: Cong Wang <xiyou.wangcong@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Willy Tarreau <w@xxxxxx> --- 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 15d46b9..0a31f2c 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -814,10 +814,8 @@ 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); @@ -835,7 +833,6 @@ 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); kfree(a); return err; -- 2.8.0.rc2.1.gbe9624a