4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xin Long <lucien.xin@xxxxxxxxx> [ Upstream commit 6d18c732b95c0a9d35e9f978b4438bba15412284 ] Since commit 76b91c32dd86 ("bridge: stp: when using userspace stp stop kernel hello and hold timers"), bridge would not start hello_timer if stp_enabled is not KERNEL_STP when br_dev_open. The problem is even if users set stp_enabled with KERNEL_STP later, the timer will still not be started. It causes that KERNEL_STP can not really work. Users have to re-ifup the bridge to avoid this. This patch is to fix it by starting br->hello_timer when enabling KERNEL_STP in br_stp_start. As an improvement, it's also to start hello_timer again only when br->stp_enabled is KERNEL_STP in br_hello_timer_expired, there is no reason to start the timer again when it's NO_STP. Fixes: 76b91c32dd86 ("bridge: stp: when using userspace stp stop kernel hello and hold timers") Reported-by: Haidong Li <haili@xxxxxxxxxx> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx> Acked-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx> Reviewed-by: Ivan Vecera <cera@xxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/bridge/br_stp_if.c | 1 + net/bridge/br_stp_timer.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) --- a/net/bridge/br_stp_if.c +++ b/net/bridge/br_stp_if.c @@ -185,6 +185,7 @@ static void br_stp_start(struct net_brid br_debug(br, "using kernel STP\n"); /* To start timers on any ports left in blocking */ + mod_timer(&br->hello_timer, jiffies + br->hello_time); br_port_state_selection(br); } --- a/net/bridge/br_stp_timer.c +++ b/net/bridge/br_stp_timer.c @@ -40,7 +40,7 @@ static void br_hello_timer_expired(unsig if (br->dev->flags & IFF_UP) { br_config_bpdu_generation(br); - if (br->stp_enabled != BR_USER_STP) + if (br->stp_enabled == BR_KERNEL_STP) mod_timer(&br->hello_timer, round_jiffies(jiffies + br->hello_time)); }