From 496074f94b19574c77240d3b3f84cfb1097de51d Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 14 Nov 2019 14:31:28 -0800 Subject: blk-cgroup: cgroup_rstat_updated() shouldn't be called on cgroup1 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. Fixes: f73316482977 ("blk-cgroup: reimplement basic IO stats using cgroup rstat") Tested-by: Faiz Abbas Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- 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(); } -- cgit v1.2.3