Hi. On Tue, Oct 19, 2021 at 06:41:14PM +0800, Quanyang Wang <quanyang.wang@xxxxxxxxxxxxx> wrote: > So I add 2 "Fixes tags" here to indicate that 2 commits introduce two > different issues. AFAIU, both the changes are needed to cause the leak, a single patch alone won't cause the issue. Is that correct? (Perhaps not as I realize, see below.) But on second thought, the problem is the missing percpu_ref_exit() in the (root) cgroup release path and percpu counter would allocate the percpu_count_ptr anyway, so 4bfc0bb2c60e is only making the leak more visible. Is this correct? I agree the commit 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path") alone did nothing wrong. [On a related (but independent) note, there seems to be an optimization opportunity in not dealing with cgroup_bpf at all on the non-default hierarchies.] Regards, Michal