This is a note to let you know that I've just added the patch titled
gpio: vf610: add locking to gpio direction functions
to the 6.12-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-vf610-add-locking-to-gpio-direction-functions.patch
and it can be found in the queue-6.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d8ee40d18b024446cd9f94a57ae9eb43c6054501
Author: Johan Korsnes <johan.korsnes@xxxxxxxxxxxxx>
Date: Mon Feb 17 10:16:43 2025 +0100
gpio: vf610: add locking to gpio direction functions
[ Upstream commit 4e667a1968099c6deadee2313ecd648f8f0a8956 ]
Add locking to `vf610_gpio_direction_input|output()` functions. Without
this locking, a race condition exists between concurrent calls to these
functions, potentially leading to incorrect GPIO direction settings.
To verify the correctness of this fix, a `trylock` patch was applied,
where after a couple of reboots the race was confirmed. I.e., one user
had to wait before acquiring the lock. With this patch the race has not
been encountered. It's worth mentioning that any type of debugging
(printing, tracing, etc.) would "resolve"/hide the issue.
Fixes: 659d8a62311f ("gpio: vf610: add imx7ulp support")
Signed-off-by: Johan Korsnes <johan.korsnes@xxxxxxxxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Reviewed-by: Haibo Chen <haibo.chen@xxxxxxx>
Cc: Bartosz Golaszewski <brgl@xxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20250217091643.679644-1-johan.korsnes@xxxxxxxxxxxxx
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpio/gpio-vf610.c b/drivers/gpio/gpio-vf610.c
index c4f34a347cb6e..c36a9dbccd4dd 100644
--- a/drivers/gpio/gpio-vf610.c
+++ b/drivers/gpio/gpio-vf610.c
@@ -36,6 +36,7 @@ struct vf610_gpio_port {
struct clk *clk_port;
struct clk *clk_gpio;
int irq;
+ spinlock_t lock; /* protect gpio direction registers */
};
#define GPIO_PDOR 0x00
@@ -124,6 +125,7 @@ static int vf610_gpio_direction_input(struct gpio_chip *chip, unsigned int gpio)
u32 val;
if (port->sdata->have_paddr) {
+ guard(spinlock_irqsave)(&port->lock);
val = vf610_gpio_readl(port->gpio_base + GPIO_PDDR);
val &= ~mask;
vf610_gpio_writel(val, port->gpio_base + GPIO_PDDR);
@@ -142,6 +144,7 @@ static int vf610_gpio_direction_output(struct gpio_chip *chip, unsigned int gpio
vf610_gpio_set(chip, gpio, value);
if (port->sdata->have_paddr) {
+ guard(spinlock_irqsave)(&port->lock);
val = vf610_gpio_readl(port->gpio_base + GPIO_PDDR);
val |= mask;
vf610_gpio_writel(val, port->gpio_base + GPIO_PDDR);
@@ -297,6 +300,7 @@ static int vf610_gpio_probe(struct platform_device *pdev)
return -ENOMEM;
port->sdata = device_get_match_data(dev);
+ spin_lock_init(&port->lock);
dual_base = port->sdata->have_dual_base;
