From: Davide Caratti <dcara...@redhat.com>
Date: Tue, 27 Aug 2019 12:29:09 +0200
> Now that 'TCQ_F_CPUSTATS' bit can be cleared, depending on the value of
> 'TCQ_F_NOLOCK' bit in the parent qdisc, we need to be sure that per-cpu
> counters are present when 'reset()' is called for pfifo_fast qdiscs.
> Otherwise, the following script:
...
> can generate the following splat:
...
> Fix this by testing the value of 'TCQ_F_CPUSTATS' bit in 'qdisc->flags',
> before dereferencing 'qdisc->cpu_qstats'.
>
> Changes since v1:
> - coding style improvements, thanks to Stefano Brivio
>
> Fixes: 8a53e616de29 ("net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS,
> too")
> CC: Paolo Abeni <pab...@redhat.com>
> Reported-by: Li Shuang <shu...@redhat.com>
> Signed-off-by: Davide Caratti <dcara...@redhat.com>
Applied and queued up for v5.2 -stable.
