Re: [PATCH RESEND] mm: memcg: synchronize objcg lists with a dedicated spinlock

From: Andrew Morton
Date: Thu Feb 03 2022 - 18:19:31 EST


On Tue, 1 Feb 2022 14:33:04 -0800 Roman Gushchin <guro@xxxxxx> wrote:

> Alexander reported a circular lock dependency revealed by the mmap1
> ltp test:
> LOCKDEP_CIRCULAR (suite: ltp, case: mtest06 (mmap1))
>
> ...
>
> Fixes: bf4f059954dc ("mm: memcg/slab: obj_cgroup API")

I'm thinking it needs cc:stable. It sounds unlikely that we'll hit it
in real life, but lockdep splats are concerning and I expect downstream
kernel consumers will end up merging this anyway, for this reason.