On Fri, May 19, 2017 at 07:30:43PM +0200, Ivan Vecera wrote:
> Current bridge code incorrectly handles starting/stopping of hello and
> hold timers during STP enable/disable.
>
> 1. Timers are stopped in br_stp_start() during NO_STP->USER_STP
> transition. The timers are already stopped in NO_STP state so
> this is confusing no-op.
Hi Ivan,
Shouldn't we start hello timer in br_stp_start when NO_STP -> BR_KERNEL_STP ?
>
> 2. During USER_STP->NO_STP transition the timers are started. This
> does not make sense and is confusion because the timer should not be
> active in NO_STP state.
Yes, but what about BR_KERNEL_STP -> NO_STP in function br_stp_stop() ?
>
> Cc: davem@xxxxxxxxxxxxx
> Cc: sashok@xxxxxxxxxxxxxxxxxxx
> Cc: stephen@xxxxxxxxxxxxxxxxxx
> Cc: bridge@xxxxxxxxxxxxxxxxxxxxxxxxxx
> Cc: lucien.xin@xxxxxxxxx
> Cc: nikolay@xxxxxxxxxxxxxxxxxxx
> Signed-off-by: Ivan Vecera <cera@xxxxxxx>
> ---
> net/bridge/br_stp_if.c | 11 -----------
> 1 file changed, 11 deletions(-)
>
> diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c
> index 08341d2aa9c9..a05027027513 100644
> --- a/net/bridge/br_stp_if.c
> +++ b/net/bridge/br_stp_if.c
> @@ -150,7 +150,6 @@ static int br_stp_call_user(struct net_bridge *br, char *arg)
>
> static void br_stp_start(struct net_bridge *br)
> {
> - struct net_bridge_port *p;
> int err = -ENOENT;
>
> if (net_eq(dev_net(br->dev), &init_net))
> @@ -169,11 +168,6 @@ static void br_stp_start(struct net_bridge *br)
> if (!err) {
> br->stp_enabled = BR_USER_STP;
> br_debug(br, "userspace STP started\n");
> -
> - /* Stop hello and hold timers */
> - del_timer(&br->hello_timer);
> - list_for_each_entry(p, &br->port_list, list)
> - del_timer(&p->hold_timer);
I'm not sure if user space daemon will send bpdu or not? In comment
76b91c32dd86 ("bridge: stp: when using userspace stp stop kernel hello and
hold timers"). Nikolay said we should not handle it with BR_USER_STP.
> } else {
> br->stp_enabled = BR_KERNEL_STP;
> br_debug(br, "using kernel STP\n");
> @@ -187,7 +181,6 @@ static void br_stp_start(struct net_bridge *br)
>
> static void br_stp_stop(struct net_bridge *br)
> {
> - struct net_bridge_port *p;
> int err;
>
> if (br->stp_enabled == BR_USER_STP) {
> @@ -196,10 +189,6 @@ static void br_stp_stop(struct net_bridge *br)
> br_err(br, "failed to stop userspace STP (%d)\n", err);
>
> /* To start timers on any ports left in blocking */
> - mod_timer(&br->hello_timer, jiffies + br->hello_time);
> - list_for_each_entry(p, &br->port_list, list)
> - mod_timer(&p->hold_timer,
> - round_jiffies(jiffies + BR_HOLD_TIME));
If we do not del hello_timer. after it expired in br_hello_timer_expired(),
Our state is br->dev->flags & IFF_UP and br->stp_enabled == NO_STP, it will
call mod_timer(&br->hello_timer, round_jiffies(jiffies + br->hello_time))
and we will keep sending bpdu message even after stp stoped.
> spin_lock_bh(&br->lock);
> br_port_state_selection(br);
> spin_unlock_bh(&br->lock);
> --
So how about just like
diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c
index d8ad73b..0198f62 100644
--- a/net/bridge/br_stp_if.c
+++ b/net/bridge/br_stp_if.c
@@ -183,6 +183,7 @@ static void br_stp_start(struct net_bridge *br)
} else {
br->stp_enabled = BR_KERNEL_STP;
br_debug(br, "using kernel STP\n");
+ mod_timer(&br->hello_timer, jiffies + br->hello_time);
/* To start timers on any ports left in blocking */
br_port_state_selection(br);
@@ -202,7 +203,6 @@ static void br_stp_stop(struct net_bridge *br)
br_err(br, "failed to stop userspace STP (%d)\n", err);
/* To start timers on any ports left in blocking */
- mod_timer(&br->hello_timer, jiffies + br->hello_time);
list_for_each_entry(p, &br->port_list, list)
mod_timer(&p->hold_timer,
round_jiffies(jiffies + BR_HOLD_TIME));
@@ -211,6 +211,7 @@ static void br_stp_stop(struct net_bridge *br)
spin_unlock_bh(&br->lock);
}
+ del_timer_sync(&br->hello_timer);
br->stp_enabled = BR_NO_STP;
}
Thanks
Hangbin
