2021-05-21 20:15:36

by Zou Wei

Subject: [PATCH -next] drm: Fix PM reference leak

pm_runtime_get_sync will increment pm usage counter even it failed.
Forgetting to putting operation will result in reference leak here.
Fix it by replacing it with pm_runtime_resume_and_get to keep usage
counter balanced.

Reported-by: Hulk Robot <[email protected]>
Signed-off-by: Zou Wei <[email protected]>
---
drivers/gpu/drm/bridge/cdns-dsi.c | 2 +-
drivers/gpu/drm/vc4/vc4_hdmi.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/cdns-dsi.c b/drivers/gpu/drm/bridge/cdns-dsi.c
index 76373e3..b31281f 100644
--- a/drivers/gpu/drm/bridge/cdns-dsi.c
+++ b/drivers/gpu/drm/bridge/cdns-dsi.c
@@ -1028,7 +1028,7 @@ static ssize_t cdns_dsi_transfer(struct mipi_dsi_host *host,
struct mipi_dsi_packet packet;
int ret, i, tx_len, rx_len;

- ret = pm_runtime_get_sync(host->dev);
+ ret = pm_runtime_resume_and_get(host->dev);
if (ret < 0)
return ret;

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index c27b287..f20a65b 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -798,7 +798,7 @@ static void vc4_hdmi_encoder_pre_crtc_configure(struct drm_encoder *encoder,
unsigned long pixel_rate, hsm_rate;
int ret;

- ret = pm_runtime_get_sync(&vc4_hdmi->pdev->dev);
+ ret = pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev);
if (ret < 0) {
DRM_ERROR("Failed to retain power domain: %d\n", ret);
return;
--
2.6.2

2021-05-21 20:23:03

by Daniel Vetter

Subject: Re: [PATCH -next] drm: Fix PM reference leak

On Fri, May 21, 2021 at 09:03:06PM +0800, Zou Wei wrote:
> pm_runtime_get_sync will increment pm usage counter even it failed.
> Forgetting to putting operation will result in reference leak here.
> Fix it by replacing it with pm_runtime_resume_and_get to keep usage
> counter balanced.
>
> Reported-by: Hulk Robot <[email protected]>
> Signed-off-by: Zou Wei <[email protected]>

Looks good, but can you pls split this up into a patch per driver (vc and
bridge/cdns-dsi here)?

Thanks, Daniel

> ---
> drivers/gpu/drm/bridge/cdns-dsi.c | 2 +-
> drivers/gpu/drm/vc4/vc4_hdmi.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/cdns-dsi.c b/drivers/gpu/drm/bridge/cdns-dsi.c
> index 76373e3..b31281f 100644
> --- a/drivers/gpu/drm/bridge/cdns-dsi.c
> +++ b/drivers/gpu/drm/bridge/cdns-dsi.c
> @@ -1028,7 +1028,7 @@ static ssize_t cdns_dsi_transfer(struct mipi_dsi_host *host,
> struct mipi_dsi_packet packet;
> int ret, i, tx_len, rx_len;
>
> - ret = pm_runtime_get_sync(host->dev);
> + ret = pm_runtime_resume_and_get(host->dev);
> if (ret < 0)
> return ret;
>
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index c27b287..f20a65b 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -798,7 +798,7 @@ static void vc4_hdmi_encoder_pre_crtc_configure(struct drm_encoder *encoder,
> unsigned long pixel_rate, hsm_rate;
> int ret;
>
> - ret = pm_runtime_get_sync(&vc4_hdmi->pdev->dev);
> + ret = pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev);
> if (ret < 0) {
> DRM_ERROR("Failed to retain power domain: %d\n", ret);
> return;
> --
> 2.6.2
>

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

2021-05-24 06:39:25

by Zou Wei

Subject: Re: [PATCH -next] drm: Fix PM reference leak

Hi Daniel,

Thanks for your review, I will split the patch and resend.

On 2021/5/21 23:32, Daniel Vetter wrote:
> On Fri, May 21, 2021 at 09:03:06PM +0800, Zou Wei wrote:
>> pm_runtime_get_sync will increment pm usage counter even it failed.
>> Forgetting to putting operation will result in reference leak here.
>> Fix it by replacing it with pm_runtime_resume_and_get to keep usage
>> counter balanced.
>>
>> Reported-by: Hulk Robot <[email protected]>
>> Signed-off-by: Zou Wei <[email protected]>
>
> Looks good, but can you pls split this up into a patch per driver (vc and
> bridge/cdns-dsi here)?
>
> Thanks, Daniel
>
>> ---
>> drivers/gpu/drm/bridge/cdns-dsi.c | 2 +-
>> drivers/gpu/drm/vc4/vc4_hdmi.c | 2 +-
>> 2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/cdns-dsi.c b/drivers/gpu/drm/bridge/cdns-dsi.c
>> index 76373e3..b31281f 100644
>> --- a/drivers/gpu/drm/bridge/cdns-dsi.c
>> +++ b/drivers/gpu/drm/bridge/cdns-dsi.c
>> @@ -1028,7 +1028,7 @@ static ssize_t cdns_dsi_transfer(struct mipi_dsi_host *host,
>> struct mipi_dsi_packet packet;
>> int ret, i, tx_len, rx_len;
>>
>> - ret = pm_runtime_get_sync(host->dev);
>> + ret = pm_runtime_resume_and_get(host->dev);
>> if (ret < 0)
>> return ret;
>>
>> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
>> index c27b287..f20a65b 100644
>> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
>> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
>> @@ -798,7 +798,7 @@ static void vc4_hdmi_encoder_pre_crtc_configure(struct drm_encoder *encoder,
>> unsigned long pixel_rate, hsm_rate;
>> int ret;
>>
>> - ret = pm_runtime_get_sync(&vc4_hdmi->pdev->dev);
>> + ret = pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev);
>> if (ret < 0) {
>> DRM_ERROR("Failed to retain power domain: %d\n", ret);
>> return;
>> --
>> 2.6.2
>>
>