From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hangbin Liu Subject: Re: [PATCH net-next v2] bridge: fix hello and hold timers starting/stopping Date: Sat, 20 May 2017 13:57:20 +0800 Message-ID: <20170520055720.GA12974@leo.usersys.redhat.com> References: <20170519173043.10201-1-cera@cera.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, davem@davemloft.net, sashok@cumulusnetworks.com, stephen@networkplumber.org, bridge@lists.linux-foundation.org, lucien.xin@gmail.com, nikolay@cumulusnetworks.com To: Ivan Vecera Return-path: Received: from mail-pf0-f193.google.com ([209.85.192.193]:35991 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932254AbdETF5i (ORCPT ); Sat, 20 May 2017 01:57:38 -0400 Received: by mail-pf0-f193.google.com with SMTP id n23so11567268pfb.3 for ; Fri, 19 May 2017 22:57:38 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20170519173043.10201-1-cera@cera.cz> Sender: netdev-owner@vger.kernel.org List-ID: 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@davemloft.net > Cc: sashok@cumulusnetworks.com > Cc: stephen@networkplumber.org > Cc: bridge@lists.linux-foundation.org > Cc: lucien.xin@gmail.com > Cc: nikolay@cumulusnetworks.com > Signed-off-by: Ivan Vecera > --- > 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