linux-kernel - Re: [PATCH 1/2] vfio: platform: Fix reset module leak in error path

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Message-ID: <CAMuHMdVkTy=TELjG0Jh7HMDe5075EHSebpNUWqBDt+6ik_Aixw@mail.gmail.com>
Date:   Wed, 21 Feb 2018 17:07:14 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Auger Eric <eric.auger@...hat.com>
Cc:     Geert Uytterhoeven <geert+renesas@...der.be>,
        Baptiste Reynal <b.reynal@...tualopensystems.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        KVM list <kvm@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] vfio: platform: Fix reset module leak in error path

Hi Eric,

On Wed, Feb 14, 2018 at 10:32 AM, Geert Uytterhoeven
<geert@...ux-m68k.org> wrote:
> On Wed, Feb 14, 2018 at 9:36 AM, Auger Eric <eric.auger@...hat.com> wrote:
>> If I am not wrong we also leak the reset_module if
>> vfio_platform_get_reset() fails to find the reset function (of_reset ==
>> NULL), in which case we should do the module_put() in
>> vfio_platform_get_reset().
>
> Correct. Will look into fixing it...

Upon second look, I don't think there's a leak in vfio_platform_get_reset().

If try_module_get() succeeded, there will always be a valid reset function
(unless someone registered a vfio_reset_handler with a NULL reset function).

Or do you mean the call to request_module()?
That one doesn't do a module_get(), it merely tries to load a module.
Hence there's no need to do a module_put() afterwards.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds