del_timer() does not wait until the timer handler finishing.
This means that the timer handler may still be running after
the driver's remove function has finished, which would result
in a use-after-free.
Fix it by calling del_timer_sync(), which makes sure the timer
handler has finished.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 drivers/hte/hte-tegra194-test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hte/hte-tegra194-test.c b/drivers/hte/hte-tegra194-test.c
index bc3ab18dfdc5..f69a274a7d8d 100644
--- a/drivers/hte/hte-tegra194-test.c
+++ b/drivers/hte/hte-tegra194-test.c
@@ -220,7 +220,7 @@ static int tegra_hte_test_remove(struct platform_device *pdev)
 	free_irq(hte.gpio_in_irq, &hte);
 	gpiod_put(hte.gpio_in);
 	gpiod_put(hte.gpio_out);
-	del_timer(&hte.timer);
+	del_timer_sync(&hte.timer);
 
 	return 0;
 }
-- 
2.25.1

Reviewed-by: Dipen Patel

Acked-by: Dipen Patel

On 5/6/22 1:48 AM, Yang Yingliang wrote:
> del_timer() does not wait until the timer handler finishing.
> This means that the timer handler may still be running after
> the driver's remove function has finished, which would result
> in a use-after-free.
> Fix it by calling del_timer_sync(), which makes sure the timer
> handler has finished.
>
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
>  drivers/hte/hte-tegra194-test.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hte/hte-tegra194-test.c b/drivers/hte/hte-tegra194-test.c
> index bc3ab18dfdc5..f69a274a7d8d 100644
> --- a/drivers/hte/hte-tegra194-test.c
> +++ b/drivers/hte/hte-tegra194-test.c
> @@ -220,7 +220,7 @@ static int tegra_hte_test_remove(struct platform_device *pdev)
>  	free_irq(hte.gpio_in_irq, &hte);
>  	gpiod_put(hte.gpio_in);
>  	gpiod_put(hte.gpio_out);
> -	del_timer(&hte.timer);
> +	del_timer_sync(&hte.timer);
>  
>  	return 0;
>  }