[PATCH 1/2] gpio: sim: dispose of irq mappings before destroying the irq_sim domain

From: Bartosz Golaszewski
Date: Tue Aug 22 2023 - 03:51:38 EST


From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>

If a GPIO simulator device is unbound with interrupts still requested,
we will hit a use-after-free issue in __irq_domain_deactivate_irq(). The
owner of the irq domain must dispose of all mappings before destroying
the domain object.

Fixes: cb8c474e79be ("gpio: sim: new testing module")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
---
drivers/gpio/gpio-sim.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index f1f6f1c32987..27515384aa10 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -291,6 +291,18 @@ static void gpio_sim_mutex_destroy(void *data)
mutex_destroy(lock);
}

+static void gpio_sim_dispose_mappings(void *data)
+{
+ struct gpio_sim_chip *chip = data;
+ unsigned int i, irq;
+
+ for (i = 0; i < chip->gc.ngpio; i++) {
+ irq = irq_find_mapping(chip->irq_sim, i);
+ if (irq)
+ irq_dispose_mapping(irq);
+ }
+}
+
static void gpio_sim_sysfs_remove(void *data)
{
struct gpio_sim_chip *chip = data;
@@ -406,6 +418,10 @@ static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev)
if (IS_ERR(chip->irq_sim))
return PTR_ERR(chip->irq_sim);

+ ret = devm_add_action_or_reset(dev, gpio_sim_dispose_mappings, chip);
+ if (ret)
+ return ret;
+
mutex_init(&chip->lock);
ret = devm_add_action_or_reset(dev, gpio_sim_mutex_destroy,
&chip->lock);
--
2.39.2