Hi,
On 15/11/19 4:01 AM, Tejun Heo wrote:
> Currently, cgroup rstat is supported only on cgroup2 hierarchy and
> rstat functions shouldn't be called on cgroup1 cgroups. While
> converting blk-cgroup core statistics to rstat, f73316482977
> ("blk-cgroup: reimplement basic IO stats using cgroup rstat")
> accidentally ended up calling cgroup_rstat_updated() on cgroup1
> cgroups causing crashes.
>
> Longer term, we probably should add cgroup1 support to rstat but for
> now let's mask the call directly.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Fixes: f73316482977 ("blk-cgroup: reimplement basic IO stats using cgroup rstat")
Tested-by: Faiz Abbas <faiz_abbas@xxxxxx>
> ---
> include/linux/blk-cgroup.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
> index 48a66738143d..19394c77ed99 100644
> --- a/include/linux/blk-cgroup.h
> +++ b/include/linux/blk-cgroup.h
> @@ -626,7 +626,8 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q,
> bis->cur.ios[rwd]++;
>
> u64_stats_update_end(&bis->sync);
> - cgroup_rstat_updated(blkg->blkcg->css.cgroup, cpu);
> + if (cgroup_subsys_on_dfl(io_cgrp_subsys))
> + cgroup_rstat_updated(blkg->blkcg->css.cgroup, cpu);
> put_cpu();
> }
>
>
Thanks,
Faiz
