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From: David Miller <>
Subject: Re: [PATCH v4 1/2] cgroup: memcg: net: do not associate sock with unrelated cgroup
Date: Tue, 10 Mar 2020 15:34:00 -0700 (PDT)	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

From: Shakeel Butt <>
Date: Mon,  9 Mar 2020 22:16:05 -0700

> We are testing network memory accounting in our setup and noticed
> inconsistent network memory usage and often unrelated cgroups network
> usage correlates with testing workload. On further inspection, it
> seems like mem_cgroup_sk_alloc() and cgroup_sk_alloc() are broken in
> irq context specially for cgroup v1.
> mem_cgroup_sk_alloc() and cgroup_sk_alloc() can be called in irq context
> and kind of assumes that this can only happen from sk_clone_lock()
> and the source sock object has already associated cgroup. However in
> cgroup v1, where network memory accounting is opt-in, the source sock
> can be unassociated with any cgroup and the new cloned sock can get
> associated with unrelated interrupted cgroup.
> Cgroup v2 can also suffer if the source sock object was created by
> process in the root cgroup or if sk_alloc() is called in irq context.
> The fix is to just do nothing in interrupt.
> WARNING: Please note that about half of the TCP sockets are allocated
> from the IRQ context, so, memory used by such sockets will not be
> accouted by the memcg.
> The stack trace of mem_cgroup_sk_alloc() from IRQ-context:
> The stack trace of mem_cgroup_sk_alloc() from IRQ-context:
> Fixes: 2d7580738345 ("mm: memcontrol: consolidate cgroup socket tracking")
> Fixes: d979a39d7242 ("cgroup: duplicate cgroup reference when cloning sockets")
> Signed-off-by: Shakeel Butt <>
> Reviewed-by: Roman Gushchin <>

Applied and queued up for -stable.

      parent reply	other threads:[~2020-03-10 22:34 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
2020-03-10  5:16 ` [PATCH v4 2/2] net: memcg: late association of sock to memcg Shakeel Butt
2020-03-10 15:53   ` Eric Dumazet
2020-03-10 22:34   ` David Miller
2020-03-10 22:38   ` Roman Gushchin
2020-03-12 14:03   ` Qian Cai
2020-03-12 14:05     ` Shakeel Butt
2020-03-10 22:34 ` David Miller [this message]

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