From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Date: Mon, 3 Nov 2025 14:11:32 +0000 (+0100)
Subject: gpiolib: fix invalid pointer access in debugfs
X-Git-Tag: v6.12.58~47
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=70180a6031056096c93ed2f47c41803268bdd91c;p=thirdparty%2Fkernel%2Fstable.git

gpiolib: fix invalid pointer access in debugfs

[ Upstream commit 2f6115ad8864cf3f48598f26c74c7c8e5c391919 ]

If the memory allocation in gpiolib_seq_start() fails, the s->private
field remains uninitialized and is later dereferenced without checking
in gpiolib_seq_stop(). Initialize s->private to NULL before calling
kzalloc() and check it before dereferencing it.

Fixes: e348544f7994 ("gpio: protect the list of GPIO devices with SRCU")
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20251103141132.53471-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e5d0d2b0d7989..967ff661e4c96 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -4997,6 +4997,8 @@ static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
 	struct gpio_device *gdev;
 	loff_t index = *pos;
 
+	s->private = NULL;
+
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return NULL;
@@ -5030,7 +5032,11 @@ static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
 
 static void gpiolib_seq_stop(struct seq_file *s, void *v)
 {
-	struct gpiolib_seq_priv *priv = s->private;
+	struct gpiolib_seq_priv *priv;
+
+	priv = s->private;
+	if (!priv)
+		return;
 
 	srcu_read_unlock(&gpio_devices_srcu, priv->idx);
 	kfree(priv);