linux-kernel - [PATCH] gpio: sim: set a limit on the number of GPIOs

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Date:   Mon, 12 Dec 2022 14:07:48 +0100
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Kent Gibson <warthog618@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
        kernel test robot <oliver.sang@...el.com>
Subject: [PATCH] gpio: sim: set a limit on the number of GPIOs

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

With the removal of ARCH_NR_GPIOS in commit 7b61212f2a07 ("gpiolib: Get
rid of ARCH_NR_GPIOS") the gpiolib core no longer sanitizes the number
of GPIOs for us. This causes the gpio-sim selftests to now fail when
setting the number of GPIOs to 99999 and expecting the probe() to fail.

Set a sane limit of 1024 on the number of simulated GPIOs and bail out
of probe if it's exceeded.

Reported-by: kernel test robot <oliver.sang@...el.com>
Link: https://lore.kernel.org/oe-lkp/202212112236.756f5db9-oliver.sang@intel.com
Fixes: 7b61212f2a07 ("gpiolib: Get rid of ARCH_NR_GPIOS")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 drivers/gpio/gpio-sim.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index 1020c2feb249..60514bc5454f 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -31,6 +31,7 @@
 
 #include "gpiolib.h"
 
+#define GPIO_SIM_NGPIO_MAX	1024
 #define GPIO_SIM_PROP_MAX	4 /* Max 3 properties + sentinel. */
 #define GPIO_SIM_NUM_ATTRS	3 /* value, pull and sentinel */
 
@@ -371,6 +372,9 @@ static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev)
 	if (ret)
 		return ret;
 
+	if (num_lines > GPIO_SIM_NGPIO_MAX)
+		return -ERANGE;
+
 	ret = fwnode_property_read_string(swnode, "gpio-sim,label", &label);
 	if (ret) {
 		label = devm_kasprintf(dev, GFP_KERNEL, "%s-%s",
-- 
2.37.2