[PATCH v1 1/1] leds: pca955x: Avoid potential overflow when filling default_label (take 2)

From: Andy Shevchenko
Date: Mon Jun 30 2025 - 05:40:28 EST


GCC compiler v8.5.0 is not happy about printing
into a too short buffer (when build with `make W=1`):

drivers/leds/leds-pca955x.c:696:5: note: 'snprintf' output between 2 and 11 bytes into a destination of size 8

Unfortunately this is a false positive from the old GCC versions,
but we may still improve the code by using '%hhu' format specifier
and reduce buffer size by 4 bytes.

Fixes: bd3d14932923 ("leds: pca955x: Avoid potential overflow when filling default_label")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202506282159.TXfvorYl-lkp@xxxxxxxxx/
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/leds/leds-pca955x.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/leds/leds-pca955x.c b/drivers/leds/leds-pca955x.c
index 42fe056b1c74..70d109246088 100644
--- a/drivers/leds/leds-pca955x.c
+++ b/drivers/leds/leds-pca955x.c
@@ -587,7 +587,7 @@ static int pca955x_probe(struct i2c_client *client)
struct pca955x_platform_data *pdata;
bool keep_psc0 = false;
bool set_default_label = false;
- char default_label[8];
+ char default_label[4];
int bit, err, reg;

chip = i2c_get_match_data(client);
@@ -693,7 +693,7 @@ static int pca955x_probe(struct i2c_client *client)
}

if (set_default_label) {
- snprintf(default_label, sizeof(default_label), "%u", i);
+ snprintf(default_label, sizeof(default_label), "%hhu", i);
init_data.default_label = default_label;
} else {
init_data.default_label = NULL;
--
2.47.2