[PATCH 1/2] coresight: Fix clock refcount imbalance on platform remove

[Yeoreum Yun]

Reviewed-by: Yeoreum Yun <yeoreum.yun at arm.com>

On Wed, Jul 01, 2026 at 02:05:02PM +0800, Jie Gan wrote:
> coresight_get_enable_clocks() enables the programming clock and the
> optional AT clock through devm_clk_get_optional_enabled(), which also
> registers a devm action to call clk_disable_unprepare() when the driver
> detaches.
> 
> After probe, pm_runtime_put() allows the device to suspend and the
> runtime suspend callback disables the same clocks. During remove the
> device is left runtime suspended, so pm_runtime_disable() freezes it
> with the clocks already disabled. The devm cleanup that runs afterwards
> calls clk_disable_unprepare() a second time, underflowing the clock
> enable refcount.
> 
> Resume the device with pm_runtime_get_sync() before pm_runtime_disable()
> so the clocks are enabled again and balance the devm-managed disable.
> 
> This affects all CoreSight platform drivers that obtain their clocks
> through coresight_get_enable_clocks(): catu, cpu-debug, ctcu, etm4x,
> funnel, replicator, stm, tmc and tpiu.
> 
> Fixes: 1abc1b212eff ("coresight: Appropriately disable programming clocks")
> Signed-off-by: Jie Gan <jie.gan at oss.qualcomm.com>
> ---
>  drivers/hwtracing/coresight/coresight-catu.c       | 1 +
>  drivers/hwtracing/coresight/coresight-cpu-debug.c  | 1 +
>  drivers/hwtracing/coresight/coresight-ctcu-core.c  | 1 +
>  drivers/hwtracing/coresight/coresight-etm4x-core.c | 1 +
>  drivers/hwtracing/coresight/coresight-funnel.c     | 1 +
>  drivers/hwtracing/coresight/coresight-replicator.c | 1 +
>  drivers/hwtracing/coresight/coresight-stm.c        | 1 +
>  drivers/hwtracing/coresight/coresight-tmc-core.c   | 1 +
>  drivers/hwtracing/coresight/coresight-tpiu.c       | 1 +
>  9 files changed, 9 insertions(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c
> index ad8dafea7d2f..f7e501e6cbd7 100644
> --- a/drivers/hwtracing/coresight/coresight-catu.c
> +++ b/drivers/hwtracing/coresight/coresight-catu.c
> @@ -647,6 +647,7 @@ static void catu_platform_remove(struct platform_device *pdev)
>  		return;
>  
>  	__catu_remove(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  }
>  
> diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c
> index 3a806c1d50ea..f7efae5b5ce5 100644
> --- a/drivers/hwtracing/coresight/coresight-cpu-debug.c
> +++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c
> @@ -711,6 +711,7 @@ static void debug_platform_remove(struct platform_device *pdev)
>  		return;
>  
>  	__debug_remove(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  }
>  
> diff --git a/drivers/hwtracing/coresight/coresight-ctcu-core.c b/drivers/hwtracing/coresight/coresight-ctcu-core.c
> index 9043cad42f01..9b6da29d9735 100644
> --- a/drivers/hwtracing/coresight/coresight-ctcu-core.c
> +++ b/drivers/hwtracing/coresight/coresight-ctcu-core.c
> @@ -266,6 +266,7 @@ static void ctcu_platform_remove(struct platform_device *pdev)
>  		return;
>  
>  	ctcu_remove(pdev);
> +	pm_runtime_get_sync(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  }
>  
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index 14bb31bd6a0b..147761024c0f 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -2416,6 +2416,7 @@ static void etm4_remove_platform_dev(struct platform_device *pdev)
>  
>  	if (drvdata)
>  		etm4_remove_dev(drvdata);
> +	pm_runtime_get_sync(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  }
>  
> diff --git a/drivers/hwtracing/coresight/coresight-funnel.c b/drivers/hwtracing/coresight/coresight-funnel.c
> index 0abc11f0690c..4c5b94640e6a 100644
> --- a/drivers/hwtracing/coresight/coresight-funnel.c
> +++ b/drivers/hwtracing/coresight/coresight-funnel.c
> @@ -334,6 +334,7 @@ static void funnel_platform_remove(struct platform_device *pdev)
>  		return;
>  
>  	funnel_remove(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  }
>  
> diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
> index 2f382de357ee..2d765f1f73b3 100644
> --- a/drivers/hwtracing/coresight/coresight-replicator.c
> +++ b/drivers/hwtracing/coresight/coresight-replicator.c
> @@ -313,6 +313,7 @@ static void replicator_platform_remove(struct platform_device *pdev)
>  		return;
>  
>  	replicator_remove(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  }
>  
> diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
> index 4e860519a73f..a653f1eebeca 100644
> --- a/drivers/hwtracing/coresight/coresight-stm.c
> +++ b/drivers/hwtracing/coresight/coresight-stm.c
> @@ -1026,6 +1026,7 @@ static void stm_platform_remove(struct platform_device *pdev)
>  		return;
>  
>  	__stm_remove(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  }
>  
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
> index bc5a133ada3e..c9cf486873e2 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
> @@ -989,6 +989,7 @@ static void tmc_platform_remove(struct platform_device *pdev)
>  		return;
>  
>  	__tmc_remove(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  }
>  
> diff --git a/drivers/hwtracing/coresight/coresight-tpiu.c b/drivers/hwtracing/coresight/coresight-tpiu.c
> index 7b029d2eb389..72ac93749be1 100644
> --- a/drivers/hwtracing/coresight/coresight-tpiu.c
> +++ b/drivers/hwtracing/coresight/coresight-tpiu.c
> @@ -286,6 +286,7 @@ static void tpiu_platform_remove(struct platform_device *pdev)
>  		return;
>  
>  	__tpiu_remove(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  }
>  
> 
> -- 
> 2.34.1
> 

-- 
Sincerely,
Yeoreum Yun