From: Tejun Heo tj@kernel.org
[ Upstream commit dc79ec1b232ad2c165d381d3dd2626df4ef9b5a4 ]
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/ Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/cgroup/cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index d14575c0e464..194060a6492a 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -2178,7 +2178,7 @@ 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;
@@ -6022,7 +6022,7 @@ 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);