From 6a4117eee82dd85f11bf898bf66026764011eeb6 Mon Sep 17 00:00:00 2001 From: Aamir Ahmed Date: Sat, 5 Sep 2026 19:38:08 +0100 Subject: [PATCH] rtc: ac100: Assign .num before accessing .hws 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 ac100_rtc_register_clks() due to .num being assigned only after every clkout clock has been stored in .hws[]. With CONFIG_UBSAN_BOUNDS and a compiler that implements __counted_by (GCC 15.1+ or Clang 20.1+), this triggers an array-index-out-of-bounds report during probe, and with CONFIG_UBSAN_TRAP the first store traps. Initialize .num with AC100_CLKOUT_NUM, the number of elements .hws[] was allocated with, right after the allocation. That is the value the loop counter ends up at on the success path anyway, so the provider's behaviour is unchanged. Cc: stable@vger.kernel.org Fixes: f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by") Assisted-by: LLM Signed-off-by: Aamir Ahmed Reviewed-by: Chen-Yu Tsai Reviewed-by: Gustavo A. R. Silva Link: https://patch.msgid.link/AS8P251MB00013E724A77A355668B6CCEC8B42@AS8P251MB0001.EURP251.PROD.OUTLOOK.COM Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-ac100.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/rtc/rtc-ac100.c b/drivers/rtc/rtc-ac100.c index bba7115ff3ad..a2f465438fd0 100644 --- a/drivers/rtc/rtc-ac100.c +++ b/drivers/rtc/rtc-ac100.c @@ -317,6 +317,8 @@ static int ac100_rtc_register_clks(struct ac100_rtc_dev *chip) if (!chip->clk_data) return -ENOMEM; + chip->clk_data->num = AC100_CLKOUT_NUM; + chip->rtc_32k_clk = clk_hw_register_fixed_rate(chip->dev, AC100_RTC_32K_NAME, NULL, 0, @@ -360,7 +362,6 @@ static int ac100_rtc_register_clks(struct ac100_rtc_dev *chip) chip->clk_data->hws[i] = &clk->hw; } - chip->clk_data->num = i; ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, chip->clk_data); if (ret) goto err_unregister_rtc_32k;