[PATCH] tty: serial: samsung_tty: Fix clk resource leak issue

[PATCH] tty: serial: samsung_tty: Fix clk resource leak issue

[Xiu Jianfeng]

In the s3c24xx_serial_get_options(), calling clk_get() without clk_put()
will cause clk resource leak issue, this patch fixes it.

Fixes: b497549a035c ("[ARM] S3C24XX: Split serial driver into core and per-cpu drivers")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
---
 drivers/tty/serial/samsung_tty.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 77d1363029f5..8a3bb9832172 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -2529,9 +2529,10 @@ s3c24xx_serial_get_options(struct uart_port *port, int *baud,
 		sprintf(clk_name, "clk_uart_baud%d", clk_sel);
 
 		clk = clk_get(port->dev, clk_name);
-		if (!IS_ERR(clk))
+		if (!IS_ERR(clk)) {
 			rate = clk_get_rate(clk);
-		else
+			clk_put(clk);
+		} else
 			rate = 1;
 
 		*baud = rate / (16 * (ubrdiv + 1));
-- 
2.17.1


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Re: [PATCH] tty: serial: samsung_tty: Fix clk resource leak issue

[Greg KH]

On Mon, Nov 07, 2022 at 02:21:20PM +0800, Xiu Jianfeng wrote:
> In the s3c24xx_serial_get_options(), calling clk_get() without clk_put()
> will cause clk resource leak issue, this patch fixes it.
> 
> Fixes: b497549a035c ("[ARM] S3C24XX: Split serial driver into core and per-cpu drivers")
> Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
> ---
>  drivers/tty/serial/samsung_tty.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
> index 77d1363029f5..8a3bb9832172 100644
> --- a/drivers/tty/serial/samsung_tty.c
> +++ b/drivers/tty/serial/samsung_tty.c
> @@ -2529,9 +2529,10 @@ s3c24xx_serial_get_options(struct uart_port *port, int *baud,
>  		sprintf(clk_name, "clk_uart_baud%d", clk_sel);
>  
>  		clk = clk_get(port->dev, clk_name);
> -		if (!IS_ERR(clk))
> +		if (!IS_ERR(clk)) {
>  			rate = clk_get_rate(clk);
> -		else
> +			clk_put(clk);
> +		} else

How was this tested?

thanks,

greg k-h

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Re: [PATCH] tty: serial: samsung_tty: Fix clk resource leak issue

[Krzysztof Kozlowski]

On 07/11/2022 08:17, Greg KH wrote:
> On Mon, Nov 07, 2022 at 02:21:20PM +0800, Xiu Jianfeng wrote:
>> In the s3c24xx_serial_get_options(), calling clk_get() without clk_put()
>> will cause clk resource leak issue, this patch fixes it.
>>
>> Fixes: b497549a035c ("[ARM] S3C24XX: Split serial driver into core and per-cpu drivers")
>> Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
>> ---
>>  drivers/tty/serial/samsung_tty.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
>> index 77d1363029f5..8a3bb9832172 100644
>> --- a/drivers/tty/serial/samsung_tty.c
>> +++ b/drivers/tty/serial/samsung_tty.c
>> @@ -2529,9 +2529,10 @@ s3c24xx_serial_get_options(struct uart_port *port, int *baud,
>>  		sprintf(clk_name, "clk_uart_baud%d", clk_sel);
>>  
>>  		clk = clk_get(port->dev, clk_name);
>> -		if (!IS_ERR(clk))
>> +		if (!IS_ERR(clk)) {
>>  			rate = clk_get_rate(clk);
>> -		else
>> +			clk_put(clk);
>> +		} else
> 
> How was this tested?

The driver has such potential missing clk_put in few other places as
well: here on success path and few error paths after calling
s3c24xx_serial_enable_baudclk(). Yet I am concerned that none of these
paths were actually tested...

Best regards,
Krzysztof


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