Re: [PATCH] gpio: wcd934x: Fix shift-out-of-bounds error

[Andy Shevchenko <andy.shevchenko@xxxxxxxxx>]

On Tue, Mar 9, 2021 at 12:21 PM Srinivas Kandagatla
<srinivas.kandagatla@xxxxxxxxxx> wrote:
>
> bit-mask for pins 0 to 4 is BIT(0) to BIT(4) however we ended up with BIT(n - 1)
> which is not right, and this was caught by below usban check

It would be nice to reduce below to ~2-3 (significant) lines.

> UBSAN: shift-out-of-bounds in /workspace/dev/linux/drivers/gpio/gpio-wcd934x.c:34:14
> qcom-q6v5-mss 4080000.remoteproc: failed to acquire pdc reset
> remoteproc remoteproc2: releasing 4080000.remoteproc
> shift exponent 4294967295 is too large for 64-bit type 'long unsigned int'
> CPU: 6 PID: 155 Comm: kworker/6:2 Not tainted 5.12.0-rc1-00045-g508b7280ec3d-dirty #1396
> Hardware name: Thundercomm Dragonboard 845c (DT)
>
> Call trace:
>  dump_backtrace+0x0/0x1c0
>  show_stack+0x18/0x68
>  dump_stack+0xd8/0x134
>  ubsan_epilogue+0x10/0x58
>  __ubsan_handle_shift_out_of_bounds+0xf8/0x168
>  wcd_gpio_get_direction+0xc8/0xd8
>  gpiochip_add_data_with_key+0x4ac/0xe78
>  devm_gpiochip_add_data_with_key+0x30/0x90
>  wcd_gpio_probe+0xc8/0x118
>  platform_probe+0x6c/0x118
>  really_probe+0x24c/0x418
>  driver_probe_device+0x68/0xf0
>  __device_attach_driver+0xb4/0x110

After addressing above, FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

> Fixes: 59c324683400 ("gpio: wcd934x: Add support to wcd934x gpio controller")
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> ---
>  drivers/gpio/gpio-wcd934x.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpio/gpio-wcd934x.c b/drivers/gpio/gpio-wcd934x.c
> index 1cbce5990855..97e6caedf1f3 100644
> --- a/drivers/gpio/gpio-wcd934x.c
> +++ b/drivers/gpio/gpio-wcd934x.c
> @@ -7,7 +7,7 @@
>  #include <linux/slab.h>
>  #include <linux/of_device.h>
>
> -#define WCD_PIN_MASK(p) BIT(p - 1)
> +#define WCD_PIN_MASK(p) BIT(p)
>  #define WCD_REG_DIR_CTL_OFFSET 0x42
>  #define WCD_REG_VAL_CTL_OFFSET 0x43
>  #define WCD934X_NPINS          5
> --
> 2.21.0
>


-- 
With Best Regards,
Andy Shevchenko