[PATCH v3] iommu/msm: Fix dangling list entry on probe failure

[Weimin Xiong]

Move the list_add() call to the end of msm_iommu_probe() instead of
adding cleanup paths, which avoids the dangling list entry problem
entirely (suggested by Mukesh Ojha).

This approach simplifies the code by ensuring the iommu device is
never added to the global list until after all potential failure
points have passed.

Changes in v3:
- Move list_add() to the end instead of adding cleanup labels
  (suggested by Mukesh Ojha)

Changes in v2:
- Resend the former patch 4/4 independently; patches 1-3 from v1
  are dropped.
- Explain the dangling list entry and stale sysfs device consequences.
- Add Fixes and stable tags.
- No code changes.

Fixes: 42df43b36163 ("iommu/msm: Make use of iommu_device_register interface")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Weimin Xiong <xiongwm2026@xxxxxxx>
---
diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
index 0ad5ff431..9da650a82 100644
--- a/drivers/iommu/msm_iommu.c
+++ b/drivers/iommu/msm_iommu.c
@@ -778,8 +778,6 @@ static int msm_iommu_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	list_add(&iommu->dev_node, &qcom_iommu_devices);
-
 	ret = iommu_device_sysfs_add(&iommu->iommu, iommu->dev, NULL,
 				     "msm-smmu.%pa", &ioaddr);
 	if (ret) {
@@ -790,9 +788,12 @@ static int msm_iommu_probe(struct platform_device *pdev)
 	ret = iommu_device_register(&iommu->iommu, &msm_iommu_ops, &pdev->dev);
 	if (ret) {
 		pr_err("Could not register msm-smmu at %pa\n", &ioaddr);
+		iommu_device_sysfs_remove(&iommu->iommu);
 		return ret;
 	}
 
+	list_add(&iommu->dev_node, &qcom_iommu_devices);
+
 	pr_info("device mapped at %p, irq %d with %d ctx banks\n",
 		iommu->base, iommu->irq, iommu->ncb);
 
-- 
2.34.1