Re: [PATCH v3] drm/bridge: synopsys: dw-dp: fix error paths of dw_dp_bind

[Louis Chauvet <louis.chauvet@bootlin.com>]

On 1/2/26 16:55, Osama Abdelkader wrote:
> Fix several issues in dw_dp_bind() error handling:
> 
> 1. Missing return after drm_bridge_attach() failure - the function
>     continued execution instead of returning an error.
> 
> 2. Resource leak: drm_dp_aux_register() is not a devm function, so
>     drm_dp_aux_unregister() must be called on all error paths after
>     aux registration succeeds. This affects errors from:
>     - drm_bridge_attach()
>     - phy_init()
>     - devm_add_action_or_reset()
>     - platform_get_irq()
>     - devm_request_threaded_irq()
> 
> 3. Bug fix: platform_get_irq() returns the IRQ number or a negative
>     error code, but the error path was returning ERR_PTR(ret) instead
>     of ERR_PTR(dp->irq).
> 
> Use a goto label for cleanup to ensure consistent error handling.
> 
> Fixes: 86eecc3a9c2e ("drm/bridge: synopsys: Add DW DPTX Controller support library")
> Cc: stable@vger.kernel.org
> 
> Signed-off-by: Osama Abdelkader <osama.abdelkader@gmail.com>

Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>

> ---
> v3:
> - Add resource leak fixes for all error paths after drm_dp_aux_register()
> - Fix platform_get_irq() error handling bug
> - Use goto pattern for cleanup as suggested by reviewer
> 
> v2:
> - use concise error message
> - add Fixes and Cc tags
> ---
>   drivers/gpu/drm/bridge/synopsys/dw-dp.c | 20 ++++++++++++++------
>   1 file changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
> index 82aaf74e1bc0..432342452484 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
> @@ -2062,33 +2062,41 @@ struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
>   	}
>   
>   	ret = drm_bridge_attach(encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> -	if (ret)
> +	if (ret) {
>   		dev_err_probe(dev, ret, "Failed to attach bridge\n");
> +		goto unregister_aux;
> +	}
>   
>   	dw_dp_init_hw(dp);
>   
>   	ret = phy_init(dp->phy);
>   	if (ret) {
>   		dev_err_probe(dev, ret, "phy init failed\n");
> -		return ERR_PTR(ret);
> +		goto unregister_aux;
>   	}
>   
>   	ret = devm_add_action_or_reset(dev, dw_dp_phy_exit, dp);
>   	if (ret)
> -		return ERR_PTR(ret);
> +		goto unregister_aux;
>   
>   	dp->irq = platform_get_irq(pdev, 0);
> -	if (dp->irq < 0)
> -		return ERR_PTR(ret);
> +	if (dp->irq < 0) {
> +		ret = dp->irq;
> +		goto unregister_aux;
> +	}
>   
>   	ret = devm_request_threaded_irq(dev, dp->irq, NULL, dw_dp_irq,
>   					IRQF_ONESHOT, dev_name(dev), dp);
>   	if (ret) {
>   		dev_err_probe(dev, ret, "failed to request irq\n");
> -		return ERR_PTR(ret);
> +		goto unregister_aux;
>   	}
>   
>   	return dp;
> +
> +unregister_aux:
> +	drm_dp_aux_unregister(&dp->aux);
> +	return ERR_PTR(ret);
>   }
>   EXPORT_SYMBOL_GPL(dw_dp_bind);
>