This is a note to let you know that I've just added the patch titled
gpio: gpiolib-of: Fix refcount bugs in of_mm_gpiochip_add_data()
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
gpio-gpiolib-of-fix-refcount-bugs-in-of_mm_gpiochip_.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f994b259e7ea9ab3fef589a92772267b3721f864
Author: Liang He <windhl@xxxxxxx>
Date: Mon Jul 11 20:52:38 2022 +0800
gpio: gpiolib-of: Fix refcount bugs in of_mm_gpiochip_add_data()
[ Upstream commit 5d07a692f9562f9c06e62cce369e9dd108173a0f ]
We should use of_node_get() when a new reference of device_node
is created. It is noted that the old reference stored in
'mm_gc->gc.of_node' should also be decreased.
This patch is based on the fact that there is a call site in function
'qe_add_gpiochips()' of src file 'drivers\soc\fsl\qe\gpio.c'. In this
function, of_mm_gpiochip_add_data() is contained in an iteration of
for_each_compatible_node() which will automatically increase and
decrease the refcount. So we need additional of_node_get() for the
reference escape in of_mm_gpiochip_add_data().
Fixes: a19e3da5bc5f ("of/gpio: Kill of_gpio_chip and add members directly to gpio_chip")
Signed-off-by: Liang He <windhl@xxxxxxx>
Signed-off-by: Bartosz Golaszewski <brgl@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index b1dcd2dd52e6..73807c897391 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -734,7 +734,8 @@ int of_mm_gpiochip_add_data(struct device_node *np,
if (mm_gc->save_regs)
mm_gc->save_regs(mm_gc);
- mm_gc->gc.of_node = np;
+ of_node_put(mm_gc->gc.of_node);
+ mm_gc->gc.of_node = of_node_get(np);
ret = gpiochip_add_data(gc, data);
if (ret)
@@ -742,6 +743,7 @@ int of_mm_gpiochip_add_data(struct device_node *np,
return 0;
err2:
+ of_node_put(np);
iounmap(mm_gc->regs);
err1:
kfree(gc->label);
