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Subject[PATCH] mdio-mux-gpio: Remove VLA usage
In the quest to remove all stack VLA usage from the kernel[1], this
allocates the values buffer during the callback instead of putting it
on the stack.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/net/phy/mdio-mux-gpio.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/mdio-mux-gpio.c b/drivers/net/phy/mdio-mux-gpio.c
index 082ffef0dec4..e99994f4ed50 100644
--- a/drivers/net/phy/mdio-mux-gpio.c
+++ b/drivers/net/phy/mdio-mux-gpio.c
@@ -26,18 +26,23 @@ static int mdio_mux_gpio_switch_fn(int current_child, int desired_child,
void *data)
{
struct mdio_mux_gpio_state *s = data;
- int values[s->gpios->ndescs];
+ int *values;
unsigned int n;

if (current_child == desired_child)
return 0;

+ values = kmalloc_array(s->gpios->ndescs, sizeof(*values), GFP_KERNEL);
+ if (!values)
+ return -ENOMEM;
+
for (n = 0; n < s->gpios->ndescs; n++)
values[n] = (desired_child >> n) & 1;

gpiod_set_array_value_cansleep(s->gpios->ndescs, s->gpios->desc,
values);

+ kfree(values);
return 0;
}

--
2.17.0

--
Kees Cook
Pixel Security

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