From: Tejun Heo <tj@kernel.org>
Date: Thu, 14 Nov 2019 14:31:28 -0800
Subject: [PATCH] blk-cgroup: cgroup_rstat_updated() shouldn't be called on
Git-commit: 496074f94b19574c77240d3b3f84cfb1097de51d
Patch-mainline: v5.5-rc1
References: bsc#1175995,jsc#SLE-15608
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 <faiz_abbas@ti.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
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();
}
--
2.16.4