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    SubjectRe: [PATCH] drm/sun4i: tcon-top: Use struct_size() in devm_kzalloc()
    On Thu, Aug 23, 2018 at 6:05 PM, Gustavo A. R. Silva
    <gustavo@embeddedor.com> wrote:
    > One of the more common cases of allocation size calculations is finding
    > the size of a structure that has a zero-sized array at the end, along
    > with memory for some number of elements for that array. For example:
    >
    > struct foo {
    > int stuff;
    > void *entry[];
    > };
    >
    > instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
    >
    > Instead of leaving these open-coded and prone to type mistakes, we can
    > now use the new struct_size() helper:
    >
    > instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);
    >
    > This issue was detected with the help of Coccinelle.
    >
    > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

    Reviewed-by: Kees Cook <keescook@chromium.org>

    -Kees

    > ---
    > drivers/gpu/drm/sun4i/sun8i_tcon_top.c | 3 +--
    > 1 file changed, 1 insertion(+), 2 deletions(-)
    >
    > diff --git a/drivers/gpu/drm/sun4i/sun8i_tcon_top.c b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
    > index 55fe398..3040a79 100644
    > --- a/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
    > +++ b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
    > @@ -129,8 +129,7 @@ static int sun8i_tcon_top_bind(struct device *dev, struct device *master,
    > if (!tcon_top)
    > return -ENOMEM;
    >
    > - clk_data = devm_kzalloc(dev, sizeof(*clk_data) +
    > - sizeof(*clk_data->hws) * CLK_NUM,
    > + clk_data = devm_kzalloc(dev, struct_size(clk_data, hws, CLK_NUM),
    > GFP_KERNEL);
    > if (!clk_data)
    > return -ENOMEM;
    > --
    > 2.7.4
    >



    --
    Kees Cook
    Pixel Security

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