linux-kernel - Re: [PATCH v2] vmw_balloon: fixing double free when batching mode is off

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Message-ID: <CAHcwAbTEjs6+oPYRJ1HTj--Xh6tORygYUL6aU9tMOJ1KHP_eKQ@mail.gmail.com>
Date:   Mon, 16 Apr 2018 13:36:20 +0200
From:   Oleksandr Natalenko <oleksandr@...hat.com>
To:     Nadav Amit <namit@...are.com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Xavier Deguillard <xdeguillard@...are.com>,
        pv-drivers <pv-drivers@...are.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Gil Kupfer <gilkup@...il.com>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "ldu@...hat.com" <ldu@...hat.com>
Subject: Re: [PATCH v2] vmw_balloon: fixing double free when batching mode is off

Hello.

On Fri, Mar 23, 2018 at 9:42 AM, Oleksandr Natalenko
<oleksandr@...hat.com> wrote:
>> Actually, rechecking the bug description, I might have rushed. The bug that
>> I encountered is related to the vunmap() but it is only caused when batching
>> is off, while the bug you reported has batching on.
>>
>> It seems that your sources support batching but do not include b91f108a3d54
>> (“VMware balloon: Treat init like reset”), which I think would have solved
>> the problem. I don’t see a mainline kernel that supports batching and does
>> not have this patch, so it would be helpful to see the exact module that you
>> use.
>
> Correct. The hash is d7568c130d0d0ff1fc5b364fc879b91f108a3d54, actually, though.
> Yes, we miss this commit in our code base, but also we've already
> provided a test kernel
> with this commit included to the customer. Unfortunately, we have no answer yet.

At least for one customer I can confirm that the kernel built with
both d7568c130 and the proposed patch fixes the issue.

Thanks.

-- 
Best regards,
  Oleksandr Natalenko (post-factum)
  Senior Software Maintenance Engineer