The formats array is allocated separately with devm_kcalloc() and only
referenced through the fimc_context. Make it a flexible array member at
the end of the context and allocate both in one go with struct_size().

Annotate it with __counted_by(num_formats) so the array accesses can be
bounds checked with FORTIFY_SOURCE and UBSAN_BOUNDS.

Assisted-by: LLM
Signed-off-by: Rosen Penev <[email protected]>
---
 drivers/gpu/drm/exynos/exynos_drm_fimc.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimc.c 
b/drivers/gpu/drm/exynos/exynos_drm_fimc.c
index 09e33a26caaf..079d24d0671c 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimc.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimc.c
@@ -99,7 +99,6 @@ struct fimc_context {
        void            *dma_priv;
        struct device   *dev;
        struct exynos_drm_ipp_task      *task;
-       struct exynos_drm_ipp_formats   *formats;
        unsigned int                    num_formats;
 
        void __iomem    *regs;
@@ -108,6 +107,7 @@ struct fimc_context {
        struct fimc_scaler      sc;
        int     id;
        int     irq;
+       struct exynos_drm_ipp_formats   formats[] __counted_by(num_formats);
 };
 
 static u32 fimc_read(struct fimc_context *ctx, u32 reg)
@@ -1273,20 +1273,16 @@ static int fimc_probe(struct platform_device *pdev)
        if (exynos_drm_check_fimc_device(dev) != 0)
                return -ENODEV;
 
-       ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+       num_formats = ARRAY_SIZE(fimc_formats) + ARRAY_SIZE(fimc_tiled_formats);
+       ctx = devm_kzalloc(dev, struct_size(ctx, formats, num_formats), 
GFP_KERNEL);
        if (!ctx)
                return -ENOMEM;
 
+       ctx->num_formats = num_formats;
+       formats = ctx->formats;
        ctx->dev = dev;
        ctx->id = of_alias_get_id(dev->of_node, "fimc");
 
-       /* construct formats/limits array */
-       num_formats = ARRAY_SIZE(fimc_formats) + ARRAY_SIZE(fimc_tiled_formats);
-       formats = devm_kcalloc(dev, num_formats, sizeof(*formats),
-                              GFP_KERNEL);
-       if (!formats)
-               return -ENOMEM;
-
        /* linear formats */
        if (ctx->id < 3) {
                limits = fimc_4210_limits_v1;
@@ -1320,9 +1316,6 @@ static int fimc_probe(struct platform_device *pdev)
                formats[j].num_limits = num_limits;
        }
 
-       ctx->formats = formats;
-       ctx->num_formats = num_formats;
-
        /* resource memory */
        ctx->regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(ctx->regs))
-- 
2.56.0


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