From: "Michael S. Tsirkin" <mst@redhat.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
David Rientjes <rientjes@google.com>,
Vladimir Davydov <vdavydov@parallels.com>,
Michal Hocko <mhocko@suse.com>
Subject: Re: [RFC PATCH 5/6] vhost, mm: make sure that oom_reaper doesn't reap memory read by vhost
Date: Mon, 4 Jul 2016 00:17:55 +0300 [thread overview]
Message-ID: <20160703215250-mutt-send-email-mst@redhat.com> (raw)
In-Reply-To: <20160703164723.GA30151@redhat.com>
On Sun, Jul 03, 2016 at 06:47:23PM +0200, Oleg Nesterov wrote:
> On 07/03, Michael S. Tsirkin wrote:
> >
> > On Sun, Jul 03, 2016 at 05:18:29PM +0200, Oleg Nesterov wrote:
> > >
> > > Well, we are going to kill all tasks which share this memory. I mean, ->mm.
> > > If "sharing memory with another task" means, say, a file, then this memory
> > > won't be unmapped (if shared).
> > >
> > > So let me ask again... Suppose, say, QEMU does VHOST_SET_OWNER and then we
> > > unmap its (anonymous/non-shared) memory. Who else's memory can be corrupted?
> >
> > As you say, I mean anyone who shares memory with QEMU through a file.
>
> And in this case vhost_worker() reads the anonymous memory of QEMU process,
> not the memory which can be shared with another task, correct?
>
> And if QEMU simply crashes, this can't affect anyone who shares memory with
> QEMU through a file, yes?
>
> Oleg.
Well no - the VM memory is not always anonymous memory. It can be an
mmaped file.
--
MST
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next prev parent reply other threads:[~2016-07-03 21:18 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-01 9:26 [RFC PATCH 0/6] fortify oom killer even more Michal Hocko
2016-07-01 9:26 ` [RFC PATCH 1/6] oom: keep mm of the killed task available Michal Hocko
2016-07-03 2:45 ` Tetsuo Handa
2016-07-07 8:24 ` Michal Hocko
2016-07-07 11:48 ` Tetsuo Handa
2016-07-07 13:32 ` Michal Hocko
2016-07-01 9:26 ` [RFC PATCH 2/6] oom, suspend: fix oom_killer_disable vs. pm suspend properly Michal Hocko
2016-07-01 9:26 ` [RFC PATCH 3/6] exit, oom: postpone exit_oom_victim to later Michal Hocko
2016-07-01 9:26 ` [RFC PATCH 4/6] oom, oom_reaper: consider mmget_not_zero as a failure Michal Hocko
2016-07-01 9:26 ` [RFC PATCH 5/6] vhost, mm: make sure that oom_reaper doesn't reap memory read by vhost Michal Hocko
2016-07-03 13:47 ` Oleg Nesterov
2016-07-03 14:09 ` Michael S. Tsirkin
2016-07-03 15:18 ` Oleg Nesterov
2016-07-03 15:30 ` Michael S. Tsirkin
2016-07-03 16:47 ` Oleg Nesterov
2016-07-03 21:17 ` Michael S. Tsirkin [this message]
2016-07-07 8:28 ` Michal Hocko
2016-07-07 15:38 ` Michael S. Tsirkin
2016-07-08 12:29 ` Oleg Nesterov
2016-07-11 14:14 ` Michal Hocko
2016-07-12 14:33 ` Oleg Nesterov
2016-07-07 8:42 ` Michal Hocko
2016-07-07 16:46 ` Oleg Nesterov
2016-07-07 8:39 ` Michal Hocko
2016-07-22 11:09 ` Michal Hocko
2016-07-01 9:26 ` [RFC PATCH 6/6] oom, oom_reaper: allow to reap mm shared by the kthreads Michal Hocko
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