Re: [PATCH] clk: imx: Fix an out-of-bounds access in dispmix_csr_clk_dev_data

[Frank Li <Frank.li@nxp.com>]

On Sat, Jun 14, 2025 at 07:22:55PM +0800, Xiaolei Wang wrote:
> When num_parents is 4, __clk_register() occurs an out-of-bounds
> when accessing parent_names member.
>
>  BUG: KASAN: global-out-of-bounds in __clk_register+0x1844/0x20d8
>  Read of size 8 at addr ffff800086988e78 by task kworker/u24:3/59
>   Hardware name: NXP i.MX95 19X19 board (DT)
>   Workqueue: events_unbound deferred_probe_work_func
>   Call trace:
>     dump_backtrace+0x94/0xec
>     show_stack+0x18/0x24
>     dump_stack_lvl+0x8c/0xcc
>     print_report+0x398/0x5fc
>     kasan_report+0xd4/0x114
>     __asan_report_load8_noabort+0x20/0x2c
>     __clk_register+0x1844/0x20d8
>     clk_hw_register+0x44/0x110
>     __clk_hw_register_mux+0x284/0x3a8
>     imx95_bc_probe+0x4f4/0xa70
>
> Fixes: 5224b189462f ("clk: imx: add i.MX95 BLK CTL clk driver")
> Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>
> ---
>  drivers/clk/imx/clk-imx95-blk-ctl.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clk/imx/clk-imx95-blk-ctl.c b/drivers/clk/imx/clk-imx95-blk-ctl.c
> index 25974947ad0c..fd11932b12b3 100644
> --- a/drivers/clk/imx/clk-imx95-blk-ctl.c
> +++ b/drivers/clk/imx/clk-imx95-blk-ctl.c
> @@ -223,7 +223,7 @@ static const struct imx95_blk_ctl_clk_dev_data dispmix_csr_clk_dev_data[] = {
>  	[IMX95_CLK_DISPMIX_ENG0_SEL] = {
>  		.name = "disp_engine0_sel",
>  		.parent_names = (const char *[]){"videopll1", "dsi_pll", "ldb_pll_div7", },
> -		.num_parents = 4,
> +		.num_parents = 3,

Although this is simple fix, is it possible to change to

const char *parent[] = {"videopll1", "dsi_pll", "ldb_pll_div7"}
num_parents = ARRAY_SIZE(parent);

to avoid hardcode number here.

Frank

>  		.reg = 0,
>  		.bit_idx = 0,
>  		.bit_width = 2,
> @@ -233,7 +233,7 @@ static const struct imx95_blk_ctl_clk_dev_data dispmix_csr_clk_dev_data[] = {
>  	[IMX95_CLK_DISPMIX_ENG1_SEL] = {
>  		.name = "disp_engine1_sel",
>  		.parent_names = (const char *[]){"videopll1", "dsi_pll", "ldb_pll_div7", },
> -		.num_parents = 4,
> +		.num_parents = 3,
>  		.reg = 0,
>  		.bit_idx = 2,
>  		.bit_width = 2,
> --
> 2.43.0
>