Commit dc79ec1b authored by Tejun Heo's avatar Tejun Heo
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarAbhishek Shah <abhishek.shah@columbia.edu>
Cc: Gabriel Ryan <gabe@cs.columbia.edu>
Reviewed-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/netdev/20220819072256.fn7ctciefy4fc4cu@wittgenstein/
parent c0f2df49

kernel/cgroup/cgroup.c

+2 −2
Original line number Diff line number Diff line
@@ -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);