On Thu, Feb 13, 2025 at 02:24:16PM +0300, Vitalii Mordan wrote:
> If owl_port->clk was enabled in owl_uart_probe(), it must be disabled in
> all error paths to ensure proper cleanup. However, if uart_add_one_port()
> returns an error in owl_uart_probe(), the owl_port->clk clock will not be
> disabled.
>
> Use the devm_clk_get_enabled() helper function to ensure proper call
> balance for owl_port->clk.
>
> Found by Linux Verification Center (linuxtesting.org) with Klever.
>
> Fixes: abf42d2f333b ("tty: serial: owl: add "much needed" clk_prepare_enable()")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Vitalii Mordan <mordan@xxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
- Mani
> ---
> drivers/tty/serial/owl-uart.c | 12 ++----------
> 1 file changed, 2 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c
> index 0542882cfbbe..64446820437c 100644
> --- a/drivers/tty/serial/owl-uart.c
> +++ b/drivers/tty/serial/owl-uart.c
> @@ -680,18 +680,12 @@ static int owl_uart_probe(struct platform_device *pdev)
> if (!owl_port)
> return -ENOMEM;
>
> - owl_port->clk = devm_clk_get(&pdev->dev, NULL);
> + owl_port->clk = devm_clk_get_enabled(&pdev->dev, NULL);
> if (IS_ERR(owl_port->clk)) {
> - dev_err(&pdev->dev, "could not get clk\n");
> + dev_err(&pdev->dev, "could not get and enable clk\n");
> return PTR_ERR(owl_port->clk);
> }
>
> - ret = clk_prepare_enable(owl_port->clk);
> - if (ret) {
> - dev_err(&pdev->dev, "could not enable clk\n");
> - return ret;
> - }
> -
> owl_port->port.dev = &pdev->dev;
> owl_port->port.line = pdev->id;
> owl_port->port.type = PORT_OWL;
> @@ -701,7 +695,6 @@ static int owl_uart_probe(struct platform_device *pdev)
> owl_port->port.uartclk = clk_get_rate(owl_port->clk);
> if (owl_port->port.uartclk == 0) {
> dev_err(&pdev->dev, "clock rate is zero\n");
> - clk_disable_unprepare(owl_port->clk);
> return -EINVAL;
> }
> owl_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP | UPF_LOW_LATENCY;
> @@ -725,7 +718,6 @@ static void owl_uart_remove(struct platform_device *pdev)
>
> uart_remove_one_port(&owl_uart_driver, &owl_port->port);
> owl_uart_ports[pdev->id] = NULL;
> - clk_disable_unprepare(owl_port->clk);
> }
>
> static struct platform_driver owl_uart_platform_driver = {
> --
> 2.25.1
>
--
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