public inbox for cgroups@vger.kernel.org
 help / color / mirror / Atom feed
From: Roman Gushchin <guro-b10kYP2dOMg@public.gmane.org>
To: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Alexander Egorenkov
	<egorenar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>,
	Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
	Shakeel Butt <shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
	Jeremy Linton <jeremy.linton-5wv7dgnIgG8@public.gmane.org>,
	cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH RESEND] mm: memcg: synchronize objcg lists with a dedicated spinlock
Date: Sat, 5 Feb 2022 08:58:26 -0800	[thread overview]
Message-ID: <Yf6sskyXcffxTA+b@carbon.dhcp.thefacebook.com> (raw)
In-Reply-To: <20220203151912.87d47b82c1bc3f0d56be0e3a-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>

On Thu, Feb 03, 2022 at 03:19:12PM -0800, Andrew Morton wrote:
> On Tue, 1 Feb 2022 14:33:04 -0800 Roman Gushchin <guro-b10kYP2dOMg@public.gmane.org> 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.
> 

I agree.

I'm somewhat surprised that we haven't seen any such warnings until recently,
so I guess some recent kmem accounting change made it more probable.

Anyway, it feels like it's a low risk change and I see no reasons
to not backport it to stable.

Thank you!

      parent reply	other threads:[~2022-02-05 16:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-01 22:33 [PATCH RESEND] mm: memcg: synchronize objcg lists with a dedicated spinlock Roman Gushchin
     [not found] ` <Yfm1IHmoGdyUR81T-cx5fftMpWqeCjSd+JxjunQ2O0Ztt9esIQQ4Iyu8u01E@public.gmane.org>
2022-02-01 22:48   ` Tejun Heo
     [not found]     ` <Yfm4yfrrJeTlaJZc-NiLfg/pYEd1N0TnZuCh8vA@public.gmane.org>
2022-02-01 23:26       ` Roman Gushchin
2022-02-01 23:49   ` Shakeel Butt
2022-02-02 15:58   ` Jeremy Linton
     [not found]     ` <49447f71-bb84-8e1d-e0cb-c9e482d3459b-5wv7dgnIgG8@public.gmane.org>
2022-02-02 16:19       ` Roman Gushchin
2022-02-05 12:27   ` Muchun Song
2022-02-03 23:19 ` Andrew Morton
     [not found]   ` <20220203151912.87d47b82c1bc3f0d56be0e3a-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2022-02-05 16:58     ` Roman Gushchin [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=Yf6sskyXcffxTA+b@carbon.dhcp.thefacebook.com \
    --to=guro-b10kyp2domg@public.gmane.org \
    --cc=akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org \
    --cc=cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
    --cc=egorenar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org \
    --cc=hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org \
    --cc=jeremy.linton-5wv7dgnIgG8@public.gmane.org \
    --cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
    --cc=linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org \
    --cc=longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
    --cc=shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org \
    --cc=tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox