Re: [PATCH 021/190] Revert "omapfb: fix multiple reference count leaks due to pm_runtime_get_sync"

[Greg Kroah-Hartman]

On Wed, Apr 21, 2021 at 02:58:16PM +0200, Greg Kroah-Hartman wrote:
> This reverts commit 78c2ce9bde70be5be7e3615a2ae7024ed8173087.
> 
> Commits from @umn.edu addresses have been found to be submitted in "bad
> faith" to try to test the kernel community's ability to review "known
> malicious" changes.  The result of these submissions can be found in a
> paper published at the 42nd IEEE Symposium on Security and Privacy
> entitled, "Open Source Insecurity: Stealthily Introducing
> Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University
> of Minnesota) and Kangjie Lu (University of Minnesota).
> 
> Because of this, all submissions from this group must be reverted from
> the kernel tree and will need to be re-reviewed again to determine if
> they actually are a valid fix.  Until that work is complete, remove this
> change to ensure that no problems are being introduced into the
> codebase.
> 
> Cc: Aditya Pakki <pakki001@xxxxxxx>
> Cc: kjlu@xxxxxxx
> Cc: wu000273@xxxxxxx
> Cc: Allison Randal <allison@xxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Enrico Weigelt <info@xxxxxxxxx>
> Cc: "Andrew F. Davis" <afd@xxxxxx>
> Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> Cc: Alexios Zavras <alexios.zavras@xxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: YueHaibing <yuehaibing@xxxxxxxxxx>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
> Cc: https
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
>  drivers/video/fbdev/omap2/omapfb/dss/dispc.c | 7 ++-----
>  drivers/video/fbdev/omap2/omapfb/dss/dsi.c   | 7 ++-----
>  drivers/video/fbdev/omap2/omapfb/dss/dss.c   | 7 ++-----
>  drivers/video/fbdev/omap2/omapfb/dss/hdmi4.c | 5 ++---
>  drivers/video/fbdev/omap2/omapfb/dss/hdmi5.c | 5 ++---
>  drivers/video/fbdev/omap2/omapfb/dss/venc.c  | 7 ++-----
>  6 files changed, 12 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dispc.c b/drivers/video/fbdev/omap2/omapfb/dss/dispc.c
> index b2d6e6df2161..285d33ce1e11 100644
> --- a/drivers/video/fbdev/omap2/omapfb/dss/dispc.c
> +++ b/drivers/video/fbdev/omap2/omapfb/dss/dispc.c
> @@ -520,11 +520,8 @@ int dispc_runtime_get(void)
>  	DSSDBG("dispc_runtime_get\n");
>  
>  	r = pm_runtime_get_sync(&dispc.pdev->dev);
> -	if (WARN_ON(r < 0)) {
> -		pm_runtime_put_sync(&dispc.pdev->dev);
> -		return r;
> -	}
> -	return 0;
> +	WARN_ON(r < 0);
> +	return r < 0 ? r : 0;
>  }
>  EXPORT_SYMBOL(dispc_runtime_get);
>  
> diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dsi.c b/drivers/video/fbdev/omap2/omapfb/dss/dsi.c
> index daa313f14335..bfa27672fe27 100644
> --- a/drivers/video/fbdev/omap2/omapfb/dss/dsi.c
> +++ b/drivers/video/fbdev/omap2/omapfb/dss/dsi.c
> @@ -1137,11 +1137,8 @@ static int dsi_runtime_get(struct platform_device *dsidev)
>  	DSSDBG("dsi_runtime_get\n");
>  
>  	r = pm_runtime_get_sync(&dsi->pdev->dev);
> -	if (WARN_ON(r < 0)) {
> -		pm_runtime_put_sync(&dsi->pdev->dev);
> -		return r;
> -	}
> -	return 0;
> +	WARN_ON(r < 0);
> +	return r < 0 ? r : 0;
>  }
>  
>  static void dsi_runtime_put(struct platform_device *dsidev)
> diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dss.c b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> index a6b1c1598040..bfc5c4c5a26a 100644
> --- a/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> +++ b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> @@ -768,11 +768,8 @@ int dss_runtime_get(void)
>  	DSSDBG("dss_runtime_get\n");
>  
>  	r = pm_runtime_get_sync(&dss.pdev->dev);
> -	if (WARN_ON(r < 0)) {
> -		pm_runtime_put_sync(&dss.pdev->dev);
> -		return r;
> -	}
> -	return 0;
> +	WARN_ON(r < 0);
> +	return r < 0 ? r : 0;
>  }
>  
>  void dss_runtime_put(void)
> diff --git a/drivers/video/fbdev/omap2/omapfb/dss/hdmi4.c b/drivers/video/fbdev/omap2/omapfb/dss/hdmi4.c
> index 800bd108e834..e8ccb2f5ea70 100644
> --- a/drivers/video/fbdev/omap2/omapfb/dss/hdmi4.c
> +++ b/drivers/video/fbdev/omap2/omapfb/dss/hdmi4.c
> @@ -39,10 +39,9 @@ static int hdmi_runtime_get(void)
>  	DSSDBG("hdmi_runtime_get\n");
>  
>  	r = pm_runtime_get_sync(&hdmi.pdev->dev);
> -	if (WARN_ON(r < 0)) {
> -		pm_runtime_put_sync(&hdmi.pdev->dev);
> +	WARN_ON(r < 0);
> +	if (r < 0)
>  		return r;
> -	}
>  
>  	return 0;
>  }
> diff --git a/drivers/video/fbdev/omap2/omapfb/dss/hdmi5.c b/drivers/video/fbdev/omap2/omapfb/dss/hdmi5.c
> index 2c03608addcd..bb59367b69c4 100644
> --- a/drivers/video/fbdev/omap2/omapfb/dss/hdmi5.c
> +++ b/drivers/video/fbdev/omap2/omapfb/dss/hdmi5.c
> @@ -43,10 +43,9 @@ static int hdmi_runtime_get(void)
>  	DSSDBG("hdmi_runtime_get\n");
>  
>  	r = pm_runtime_get_sync(&hdmi.pdev->dev);
> -	if (WARN_ON(r < 0)) {
> -		pm_runtime_put_sync(&hdmi.pdev->dev);
> +	WARN_ON(r < 0);
> +	if (r < 0)
>  		return r;
> -	}
>  
>  	return 0;
>  }
> diff --git a/drivers/video/fbdev/omap2/omapfb/dss/venc.c b/drivers/video/fbdev/omap2/omapfb/dss/venc.c
> index 905d642ff9ed..b9e722542afb 100644
> --- a/drivers/video/fbdev/omap2/omapfb/dss/venc.c
> +++ b/drivers/video/fbdev/omap2/omapfb/dss/venc.c
> @@ -348,11 +348,8 @@ static int venc_runtime_get(void)
>  	DSSDBG("venc_runtime_get\n");
>  
>  	r = pm_runtime_get_sync(&venc.pdev->dev);
> -	if (WARN_ON(r < 0)) {
> -		pm_runtime_put_sync(&venc.pdev->dev);
> -		return r;
> -	}
> -	return 0;
> +	WARN_ON(r < 0);
> +	return r < 0 ? r : 0;
>  }
>  
>  static void venc_runtime_put(void)
> -- 
> 2.31.1
> 

Messy and no one can hit this, but it looks semi-correct so I'll keep
this and drop my revert.

thanks,

greg k-h