Re: [PATCH net] net: bridge: start hello timer only if device is up

[David Miller <davem@davemloft.net>]

From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Date: Thu,  1 Jun 2017 18:07:55 +0300

> When the transition of NO_STP -> KERNEL_STP was fixed by always calling
> mod_timer in br_stp_start, it introduced a new regression which causes
> the timer to be armed even when the bridge is down, and since we stop
> the timers in its ndo_stop() function, they never get disabled if the
> device is destroyed before it's upped.
> 
> To reproduce:
> $ while :; do ip l add br0 type bridge hello_time 100; brctl stp br0 on;
> ip l del br0; done;
> 
> CC: Xin Long <lucien.xin@gmail.com>
> CC: Ivan Vecera <cera@cera.cz>
> CC: Sebastian Ott <sebott@linux.vnet.ibm.com>
> Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
> Fixes: 6d18c732b95c ("bridge: start hello_timer when enabling KERNEL_STP in br_stp_start")
> Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>

Applied and queued up for -stable.