From: "Christopherson, Sean J" <sean.j.christopherson@intel.com>
To: 'Michal Hocko' <mhocko@kernel.org>
Cc: "hannes@cmpxchg.org" <hannes@cmpxchg.org>,
"vdavydov.dev@gmail.com" <vdavydov.dev@gmail.com>,
"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: RE: [PATCH 0/2] mm/memcontrol: fix reclaim bugs in mem_cgroup_iter
Date: Tue, 2 May 2017 14:20:45 +0000 [thread overview]
Message-ID: <37306EFA9975BE469F115FDE982C075B9B704A9A@ORSMSX108.amr.corp.intel.com> (raw)
In-Reply-To: <20170502140357.GL14593@dhcp22.suse.cz>
Michal Hocko <mhocko@kernel.org> wrote:
> On Fri 28-04-17 14:55:45, Sean Christopherson wrote:
> > This patch set contains two bug fixes for mem_cgroup_iter(). The bugs
> > were found by code inspection and were confirmed via synthetic testing
> > that forcefully setup the failing conditions.
>
> I assume that you added some artificial sleeps to make those races more
> probable, right? Or did you manage to hit those issue solely from the
> userspace? I will have a look at those patches. It has been some time
> since I've had it cached. It is pretty subtle code so I would like to
> understand the urgency before I dive into this further.
> --
> Michal Hocko
> SUSE Labs
The code to prove the bugs is completely artificial, it's basically a
unit test for mem_cgroup_iter() that uses a thread barrier to all but
guarantee two threads will call mem_cgroup_iter() simultaneously. I
haven't even attempted to hit this via the actual userspace flow.
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prev parent reply other threads:[~2017-05-02 14:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-28 21:55 Sean Christopherson
2017-04-28 21:55 ` [PATCH 1/2] mm/memcontrol: check cmpxchg(iter->pos...) result in mem_cgroup_iter() Sean Christopherson
2017-04-28 21:55 ` [PATCH 2/2] mm/memcontrol: inc reclaim gen if restarting walk " Sean Christopherson
2017-05-02 14:03 ` [PATCH 0/2] mm/memcontrol: fix reclaim bugs in mem_cgroup_iter Michal Hocko
2017-05-02 14:20 ` Christopherson, Sean J [this message]
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