[PATCH] drm/sun4i: fix refcount leak in sun4i_backend_init_sat()

[PATCH] drm/sun4i: fix refcount leak in sun4i_backend_init_sat()

[Wentao Liang]

When sun4i_backend_init_sat() calls reset_control_deassert() it
increments the deassert_count of the reset controller, and must
pair that with a reset_control_assert() call to decrement it.
In the error path where clk_prepare_enable() fails, the function
returns immediately without calling reset_control_assert(), leaking
the reference count.  Other error paths, like the devm_clk_get()
failure, correctly jump to the err_assert_reset label which performs
the missing assert.

Fix the leak by using the existing err_assert_reset label in the
clk_prepare_enable error path instead of returning directly.

Cc: stable@vger.kernel.org
Fixes: 440d2c7b127a ("drm/sun4i: backend: Handle the SAT")
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
---
 drivers/gpu/drm/sun4i/sun4i_backend.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
index bc35dad53b07..c9ec5fc26f7e 100644
--- a/drivers/gpu/drm/sun4i/sun4i_backend.c
+++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
@@ -686,7 +686,7 @@ static int sun4i_backend_init_sat(struct device *dev) {
 	ret = clk_prepare_enable(backend->sat_clk);
 	if (ret) {
 		dev_err(dev, "Couldn't enable the SAT clock\n");
-		return ret;
+		goto err_assert_reset;
 	}
 
 	return 0;
-- 
2.34.1

Re: [PATCH] drm/sun4i: fix refcount leak in sun4i_backend_init_sat()

[Christophe JAILLET]

Le 07/06/2026 à 05:09, Wentao Liang a écrit :
> When sun4i_backend_init_sat() calls reset_control_deassert() it
> increments the deassert_count of the reset controller, and must
> pair that with a reset_control_assert() call to decrement it.
> In the error path where clk_prepare_enable() fails, the function
> returns immediately without calling reset_control_assert(), leaking
> the reference count.  Other error paths, like the devm_clk_get()
> failure, correctly jump to the err_assert_reset label which performs
> the missing assert.
> 
> Fix the leak by using the existing err_assert_reset label in the
> clk_prepare_enable error path instead of returning directly.
> 
> Cc: stable@vger.kernel.org
> Fixes: 440d2c7b127a ("drm/sun4i: backend: Handle the SAT")
> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
> ---
>   drivers/gpu/drm/sun4i/sun4i_backend.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
> index bc35dad53b07..c9ec5fc26f7e 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_backend.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
> @@ -686,7 +686,7 @@ static int sun4i_backend_init_sat(struct device *dev) {
>   	ret = clk_prepare_enable(backend->sat_clk);
>   	if (ret) {
>   		dev_err(dev, "Couldn't enable the SAT clock\n");
> -		return ret;
> +		goto err_assert_reset;
>   	}
>   
>   	return 0;

Hi,

another way to fix it and simplify the code at the same time would be to 
use devm_reset_control_get_exclusive_deasserted() and 
devm_clk_get_enabled().

just my 2c,

CJ

Re: [PATCH] drm/sun4i: fix refcount leak in sun4i_backend_init_sat()

[Jernej Škrabec]

Dne nedelja, 7. junij 2026 ob 05:09:50 Srednjeevropski poletni čas je Wentao Liang napisal(a):
> When sun4i_backend_init_sat() calls reset_control_deassert() it
> increments the deassert_count of the reset controller, and must
> pair that with a reset_control_assert() call to decrement it.
> In the error path where clk_prepare_enable() fails, the function
> returns immediately without calling reset_control_assert(), leaking
> the reference count.  Other error paths, like the devm_clk_get()
> failure, correctly jump to the err_assert_reset label which performs
> the missing assert.
> 
> Fix the leak by using the existing err_assert_reset label in the
> clk_prepare_enable error path instead of returning directly.
> 
> Cc: stable@vger.kernel.org
> Fixes: 440d2c7b127a ("drm/sun4i: backend: Handle the SAT")
> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>

Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>

Best regards,
Jernej