cgroup: Remove data-race around cgrp_dfl_visible

There's a seemingly harmless data-race around cgrp_dfl_visible detected by
kernel concurrency sanitizer. Let's remove it by throwing WRITE/READ_ONCE at
it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Abhishek Shah <abhishek.shah@columbia.edu>
Cc: Gabriel Ryan <gabe@cs.columbia.edu>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/netdev/20220819072256.fn7ctciefy4fc4cu@wittgenstein/
This commit is contained in:
Tejun Heo 2022-09-04 09:16:19 -10:00
parent c0f2df49cf
commit dc79ec1b23

View file

@ -2173,7 +2173,7 @@ static int cgroup_get_tree(struct fs_context *fc)
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
int ret;
cgrp_dfl_visible = true;
WRITE_ONCE(cgrp_dfl_visible, true);
cgroup_get_live(&cgrp_dfl_root.cgrp);
ctx->root = &cgrp_dfl_root;
@ -6098,7 +6098,7 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
struct cgroup *cgrp;
int ssid, count = 0;
if (root == &cgrp_dfl_root && !cgrp_dfl_visible)
if (root == &cgrp_dfl_root && !READ_ONCE(cgrp_dfl_visible))
continue;
seq_printf(m, "%d:", root->hierarchy_id);