Revisit cgroup v2 memory leak patch. LP #1886668

[Thadeu Lima de Souza Cascardo]

On Fri, Sep 18, 2020 at 11:20:04AM +0200, Allan Grue Soeby wrote:
> Hi,
> 
> A cgroup v2 memory leak patch was introduced with 5.4.0-40, but reverted
> with 5.4.0-42 due to avoid kernel crash (LP  #1886668).
> 
> 
> This as per "SAUCE: Revert "netprio_cgroup: Fix unlimited memory leak of v2
> cgroups" mentioned in
> https://lists.ubuntu.com/archives/kernel-team/2020-July/111893.html
> 
> 
> Meanwhile, the original reason for the crash seems to have been fixed
> upstream with these:
> 
>   cgroup: fix cgroup_sk_alloc() for sk_clone_lock() -  Upstream commit
> ad0f75e5f57ccbceec13274e1e242f2b5a6397e
> 
>   group: Fix sock_cgroup_data on big-endian - Upstream commit
> 14b032b8f8fce03a546dcf365454bec8c4a58d7d
> 
> 
> It seems those crash fixes are already in the code base with upstream LTS
> 5.4.53.
> 
> 
> Would you consider revisiting this issue, to get the cgroup v2 memleak fix
> back in place ?
> 
> 
> Best regards,
> 
> Allan Grue Soeby

Yes, that was on my track, but I didn't find the time to build a test for the
leak. But considering where we are on the cycle, we will have some time to work
on it.

Cascardo.