On Mon, Nov 24, 2025 at 1:11 PM Nathan Chancellor nathan@kernel.org wrote:
Commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by") annotated the hws member of 'struct clk_hw_onecell_data' with __counted_by, which informs the bounds sanitizer (UBSAN_BOUNDS) about the number of elements in .hws[], so that it can warn when .hws[] is accessed out of bounds. As noted in that change, the __counted_by member must be initialized with the number of elements before the first array access happens, otherwise there will be a warning from each access prior to the initialization because the number of elements is zero. This occurs in exynos_clkout_probe() due to .num being assigned after .hws[] has been accessed:
UBSAN: array-index-out-of-bounds in drivers/clk/samsung/clk-exynos-clkout.c:178:18 index 0 is out of range for type 'clk_hw *[*]'
Move the .num initialization to before the first access of .hws[], clearing up the warning.
Cc: stable@vger.kernel.org Fixes: f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by") Reported-by: Jochen Sprickerhof jochen@sprickerhof.de Closes: https://lore.kernel.org/aSIYDN5eyKFKoXKL@eldamar.lan/ Tested-by: Jochen Sprickerhof jochen@sprickerhof.de Signed-off-by: Nathan Chancellor nathan@kernel.org
Reviewed-by: Sam Protsenko semen.protsenko@linaro.org
drivers/clk/samsung/clk-exynos-clkout.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clk/samsung/clk-exynos-clkout.c b/drivers/clk/samsung/clk-exynos-clkout.c index 5f1a4f5e2e59..5b21025338bd 100644 --- a/drivers/clk/samsung/clk-exynos-clkout.c +++ b/drivers/clk/samsung/clk-exynos-clkout.c @@ -175,6 +175,7 @@ static int exynos_clkout_probe(struct platform_device *pdev) clkout->mux.shift = EXYNOS_CLKOUT_MUX_SHIFT; clkout->mux.lock = &clkout->slock;
clkout->data.num = EXYNOS_CLKOUT_NR_CLKS; clkout->data.hws[0] = clk_hw_register_composite(NULL, "clkout", parent_names, parent_count, &clkout->mux.hw, &clk_mux_ops, NULL, NULL, &clkout->gate.hw,@@ -185,7 +186,6 @@ static int exynos_clkout_probe(struct platform_device *pdev) goto err_unmap; }
clkout->data.num = EXYNOS_CLKOUT_NR_CLKS; ret = of_clk_add_hw_provider(clkout->np, of_clk_hw_onecell_get, &clkout->data); if (ret) goto err_clk_unreg;
base-commit: b6430552c8cd95e90bb842ce2f421e7a5381859f change-id: 20251124-exynos-clkout-fix-ubsan-bounds-error-93071375ec78
Best regards,
Nathan Chancellor nathan@kernel.org