On Wed, 9 Nov 2022 01:20:11 +0000 Shakeel Butt <shakeelb@xxxxxxxxxx> wrote: > However there is a small race window between the online CPUs traversal > of percpu_counter_sum and the CPU offline callback. The offline callback > has to traverse all the percpu_counters on the system to flush the CPU > local data which can be a lot. During that time, the CPU which is going > offline has already been published as offline to all the readers. So, as > the offline callback is running, percpu_counter_sum can be called for > one counter which has some state on the CPU going offline. Since > percpu_counter_sum only traverses online CPUs, it will skip that > specific CPU and the offline callback might not have flushed the state > for that specific percpu_counter on that offlined CPU. LGTM. What are the user-visible effects of this bug? Should we cc:stable? If so, can you identify a suitable Fixes:? Thanks.
