2017-05-19 16:45 GMT+02:00 Nikolay Aleksandrov <niko...@cumulusnetworks.com>: > On 5/19/17 5:20 PM, Xin Long wrote: >> >> 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 <ha...@redhat.com> >> Signed-off-by: Xin Long <lucien....@gmail.com> >> --- >> net/bridge/br_stp_if.c | 1 + >> net/bridge/br_stp_timer.c | 2 +- >> 2 files changed, 2 insertions(+), 1 deletion(-) >> > > This doesn't make much sense to me, how do you change from USER_STP to > KERNEL_STP without first going through NO_STP ? > > If you go through NO_STP then all will be fine because br_stp_stop will > restart > the timers if the previous val was USER_STP. > The problem occurs when KERNEL_STP is enabled if the bridge itself is already up. Then the hello_timer is not started. If the hello and hold timers should run only when KERNEL_STP is used then there are another problematic places (will send follow-up).
Ivan