linux-kernel - Re: [PATCH v2 1/8] fpga: do not access region struct after fpga_region

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Message-ID: <CAAtXAHfzhmdZ6SnheZ-DXD14dde7Ccm66jEM=Q3UWDukKsyGBA@mail.gmail.com>
Date:   Tue, 4 Sep 2018 16:41:09 -0700
From:   Moritz Fischer <moritz.fischer@...us.com>
To:     Alan Tull <atull@...nel.org>
Cc:     Jonathan Corbet <corbet@....net>,
        Randy Dunlap <rdunlap@...radead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-fpga@...r.kernel.org,
        Linux Doc Mailing List <linux-doc@...r.kernel.org>
Subject: Re: [PATCH v2 1/8] fpga: do not access region struct after fpga_region_unregister

Hi Alan,

On Tue, Sep 4, 2018 at 2:22 PM, Alan Tull <atull@...nel.org> wrote:
> A couple drivers were accessing the region struct after it had been
> freed.  Save off the pointer to the mgr before the region struct gets
> freed.
>
> Signed-off-by: Alan Tull <atull@...nel.org>
Acked-by: Moritz Fischer <mdf@...nel.org>
> ---
> v2: no change in v2 of patchset
> ---
>  drivers/fpga/dfl-fme-region.c | 4 +++-
>  drivers/fpga/of-fpga-region.c | 3 ++-
>  2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/fpga/dfl-fme-region.c b/drivers/fpga/dfl-fme-region.c
> index 0b7e19c..51a5ac2 100644
> --- a/drivers/fpga/dfl-fme-region.c
> +++ b/drivers/fpga/dfl-fme-region.c
> @@ -14,6 +14,7 @@
>   */
>
>  #include <linux/module.h>
> +#include <linux/fpga/fpga-mgr.h>
>  #include <linux/fpga/fpga-region.h>
>
>  #include "dfl-fme-pr.h"
> @@ -66,9 +67,10 @@ static int fme_region_probe(struct platform_device *pdev)
>  static int fme_region_remove(struct platform_device *pdev)
>  {
>         struct fpga_region *region = dev_get_drvdata(&pdev->dev);
> +       struct fpga_manager *mgr = region->mgr;
>
>         fpga_region_unregister(region);
> -       fpga_mgr_put(region->mgr);
> +       fpga_mgr_put(mgr);
>
>         return 0;
>  }
> diff --git a/drivers/fpga/of-fpga-region.c b/drivers/fpga/of-fpga-region.c
> index 35fabb8..052a134 100644
> --- a/drivers/fpga/of-fpga-region.c
> +++ b/drivers/fpga/of-fpga-region.c
> @@ -437,9 +437,10 @@ static int of_fpga_region_probe(struct platform_device *pdev)
>  static int of_fpga_region_remove(struct platform_device *pdev)
>  {
>         struct fpga_region *region = platform_get_drvdata(pdev);
> +       struct fpga_manager *mgr = region->mgr;
>
>         fpga_region_unregister(region);
> -       fpga_mgr_put(region->mgr);
> +       fpga_mgr_put(mgr);
>
>         return 0;
>  }
> --
> 2.7.4
>

Thanks,
Moritz