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From: Andrew Morton <akpm@linux-foundation.org>
To: Roman Gushchin <guro@fb.com>
Cc: <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
	Alexander Egorenkov <egorenar@linux.ibm.com>,
	Waiman Long <longman@redhat.com>, Tejun Heo <tj@kernel.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Shakeel Butt <shakeelb@google.com>,
	Jeremy Linton <jeremy.linton@arm.com>, <cgroups@vger.kernel.org>
Subject: Re: [PATCH RESEND] mm: memcg: synchronize objcg lists with a dedicated spinlock
Date: Thu, 3 Feb 2022 15:19:12 -0800	[thread overview]
Message-ID: <20220203151912.87d47b82c1bc3f0d56be0e3a@linux-foundation.org> (raw)
In-Reply-To: <Yfm1IHmoGdyUR81T@carbon.dhcp.thefacebook.com>

On Tue, 1 Feb 2022 14:33:04 -0800 Roman Gushchin <guro@fb.com> 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.


WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Roman Gushchin <guro@fb.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Alexander Egorenkov <egorenar@linux.ibm.com>,
	Waiman Long <longman@redhat.com>, Tejun Heo <tj@kernel.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Shakeel Butt <shakeelb@google.com>,
	Jeremy Linton <jeremy.linton@arm.com>,
	cgroups@vger.kernel.org
Subject: Re: [PATCH RESEND] mm: memcg: synchronize objcg lists with a dedicated spinlock
Date: Thu, 3 Feb 2022 15:19:12 -0800	[thread overview]
Message-ID: <20220203151912.87d47b82c1bc3f0d56be0e3a@linux-foundation.org> (raw)
In-Reply-To: <Yfm1IHmoGdyUR81T@carbon.dhcp.thefacebook.com>

On Tue, 1 Feb 2022 14:33:04 -0800 Roman Gushchin <guro@fb.com> 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.


  parent reply	other threads:[~2022-02-03 23:19 UTC|newest]

Thread overview: 18+ 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
2022-02-01 22:33 ` Roman Gushchin
2022-02-01 22:48 ` Tejun Heo
2022-02-01 22:48   ` Tejun Heo
2022-02-01 23:26   ` Roman Gushchin
2022-02-01 23:26     ` Roman Gushchin
2022-02-01 23:49 ` Shakeel Butt
2022-02-01 23:49   ` Shakeel Butt
2022-02-02 15:58 ` Jeremy Linton
2022-02-02 15:58   ` Jeremy Linton
2022-02-02 16:19   ` Roman Gushchin
2022-02-02 16:19     ` Roman Gushchin
2022-02-03 23:19 ` Andrew Morton [this message]
2022-02-03 23:19   ` Andrew Morton
2022-02-05 16:58   ` Roman Gushchin
2022-02-05 16:58     ` Roman Gushchin
2022-02-05 12:27 ` Muchun Song
2022-02-05 12:27   ` Muchun Song

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