Re: [PATCH v4 0/4] blk-cgroup: fix blkg list and policy data races

[Nilay Shroff]

On 8/2/26 4:55 PM, Yu Kuai wrote:
> From: Yu Kuai <yukuai@xxxxxxx>
>
> This set fix some problems that are reported long time ago with minimal changes,
> the blkcg_mutex refactor I'm working on can fix these problems as well, but it's
> complicated and may not land in this merge window. So I think this set should land
> in this merge window first.
>
> Patch 1 protects blkg_destroy_all()'s q->blkg_list walk with
> blkcg_mutex.
>
> Patches 2-3 fix races between blkcg_activate_policy() and concurrent
> blkg destruction.
>
> Patch 4 factors the policy data teardown loop into a helper after the
> race fixes.

This series looks good to me, however as I recall, we discussed about
protecting blkg_create() as well using ->blkcg_mutex. I remember the
blkg_create() is not protected with ->blkcg_mutex under each call path,
so would you to also cover that change in this patchset?

Thanks,
--Nilay