Re: [PATCH net-next v2] bridge: fix hello and hold timers starting/stopping
From: Hangbin Liu <hidden>
Date: 2017-05-20 05:57:38
Also in:
bridge
Subsystem:
ethernet bridge, networking [general], the rest · Maintainers:
Nikolay Aleksandrov, Ido Schimmel, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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() ?
quoted hunk ↗ jump to hunk
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 <redacted> --- 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.
quoted hunk ↗ jump to hunk
} 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