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

[Louis Chauvet]

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: sta...@vger.kernel.org

Signed-off-by: Osama Abdelkader <osama.abdelka...@gmail.com>

Reviewed-by: Louis Chauvet <louis.chau...@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);