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gpio: gpiolib-of: Fix refcount bugs in of_mm_gpiochip_add_data() 

[ Upstream commit 5d07a692f9 ]

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: a19e3da5bc ("of/gpio: Kill of_gpio_chip and add members directly to gpio_chip")
Signed-off-by: Liang He <windhl@126.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Liang He 2022-07-11 20:52:38 +08:00 committed by Greg Kroah-Hartman
parent 1750be1e9f
commit 5f3f8495ac
1 changed files with 3 additions and 1 deletions
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4
drivers/gpio/gpiolib-of.c
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@ -861,7 +861,8 @@ 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)
@ -869,6 +870,7 @@ 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);