[PATCH] gpio-uclass: fix off-by-one in gpio_request_list_by_name_nodev()

[Rasmus Villemoes]

On 20/04/2023 00.40, Simon Glass wrote:
> On Wed, 19 Apr 2023 at 22:11, Rasmus Villemoes
> <rasmus.villemoes at prevas.dk> wrote:
>>
>> By the time we jump to the err label, count represents the number of
>> gpios we've succesfully requested. So by subtracting one, we fail to
>> free the most recently requested.
>>
>> Signed-off-by: Rasmus Villemoes <rasmus.villemoes at prevas.dk>
>> ---
>>  drivers/gpio/gpio-uclass.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Reviewed-by: Simon Glass <sjg at chromium.org>
> 
> Could the tests catch this bug?

Perhaps, I don't have time to run this through, but something like

diff --git a/test/dm/gpio.c b/test/dm/gpio.c
index 0d88ec24bd..45620c1dde 100644
--- a/test/dm/gpio.c
+++ b/test/dm/gpio.c
@@ -348,6 +348,12 @@ static int dm_test_gpio_phandles(struct
unit_test_state *uts)
        ut_asserteq(-ENOENT, gpio_request_by_name(dev, "test-gpios", 5,
&desc,
                                                  0));

+       ut_assertok(gpio_request_by_name(dev, "test-gpios", 1,
&desc_list[1], 0));
+       ut_asserteq(-EBUSY, gpio_request_list_by_name(dev, "test-gpios",
+                                                     desc_list2, 2, 0));
+       ut_assertok(gpio_request_by_name(dev, "test-gpios", 0,
&desc_list[0], 0));
+       ut_assertok(gpio_free_list(dev, desc_list, 2));
+
        /* Last GPIO is ignored as it comes after <0> */
        ut_asserteq(3, gpio_request_list_by_name(dev, "test-gpios",
desc_list,
                                                 ARRAY_SIZE(desc_list), 0));

might do it. Feel free to turn that into a real patch if it works (i.e.
detects the bug without the fix).

Rasmus