[PATCH] clk: samsung: Fix UBSAN panic in samsung_clk_init()

[PATCH] clk: samsung: Fix UBSAN panic in samsung_clk_init()

[Will McVicker]

With UBSAN_ARRAY_BOUNDS=y, I'm hitting the below panic due to
dereferencing `ctx->clk_data.hws` before setting
`ctx->clk_data.num = nr_clks`. Move that up to fix the crash.

  UBSAN: array index out of bounds: 00000000f2005512 [#1] PREEMPT SMP
  <snip>
  Call trace:
   samsung_clk_init+0x110/0x124 (P)
   samsung_clk_init+0x48/0x124 (L)
   samsung_cmu_register_one+0x3c/0xa0
   exynos_arm64_register_cmu+0x54/0x64
   __gs101_cmu_top_of_clk_init_declare+0x28/0x60
   ...

Fixes: e620a1e061c4 ("drivers/clk: convert VL struct to struct_size")
Signed-off-by: Will McVicker <willmcvicker@google.com>
---
 drivers/clk/samsung/clk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/samsung/clk.c b/drivers/clk/samsung/clk.c
index 283c523763e6..8d440cf56bd4 100644
--- a/drivers/clk/samsung/clk.c
+++ b/drivers/clk/samsung/clk.c
@@ -74,12 +74,12 @@ struct samsung_clk_provider * __init samsung_clk_init(struct device *dev,
 	if (!ctx)
 		panic("could not allocate clock provider context.\n");
 
+	ctx->clk_data.num = nr_clks;
 	for (i = 0; i < nr_clks; ++i)
 		ctx->clk_data.hws[i] = ERR_PTR(-ENOENT);
 
 	ctx->dev = dev;
 	ctx->reg_base = base;
-	ctx->clk_data.num = nr_clks;
 	spin_lock_init(&ctx->lock);
 
 	return ctx;

base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b
-- 
2.48.1.502.g6dc24dfdaf-goog

Re: [PATCH] clk: samsung: Fix UBSAN panic in samsung_clk_init()

[Krzysztof Kozlowski]

On Wed, 12 Feb 2025 10:32:52 -0800, Will McVicker wrote:
> With UBSAN_ARRAY_BOUNDS=y, I'm hitting the below panic due to
> dereferencing `ctx->clk_data.hws` before setting
> `ctx->clk_data.num = nr_clks`. Move that up to fix the crash.
> 
>   UBSAN: array index out of bounds: 00000000f2005512 [#1] PREEMPT SMP
>   <snip>
>   Call trace:
>    samsung_clk_init+0x110/0x124 (P)
>    samsung_clk_init+0x48/0x124 (L)
>    samsung_cmu_register_one+0x3c/0xa0
>    exynos_arm64_register_cmu+0x54/0x64
>    __gs101_cmu_top_of_clk_init_declare+0x28/0x60
>    ...
> 
> [...]

Applied, thanks!

[1/1] clk: samsung: Fix UBSAN panic in samsung_clk_init()
      https://git.kernel.org/krzk/linux/c/d19d7345a7bcdb083b65568a11b11adffe0687af

Best regards,
-- 
Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>