Re: [PATCH] cgroup1: fix leaked context root causing sporadic NULL deref in LTP

Hello,

On Wed, Jun 16, 2021 at 08:51:57AM -0400, Paul Gortmaker wrote:

A fix would be to not leave the stale reference in fc->root as follows:

---

dput(fc->root);

•           fc->root = NULL;
  

deactivate_locked_super(sb);

...but then we are just open-coding a duplicate of fc_drop_locked() so we simply use that instead.

As this is unlikely to be a real-world problem both in probability and circumstances, I'm applying this to cgroup/for-5.14 instead of cgroup/for-5.13-fixes.

Thanks.