iommu/rockchip: prevent iommus dead loop when two masters share one IOMMU

When two masters share an IOMMU, calling ops->of_xlate during
the second master's driver init may overwrite iommu->domain set
by the first. This causes the check if (iommu->domain == domain)
in rk_iommu_attach_device() to fail, resulting in the same
iommu->node being added twice to &rk_domain->iommus, which can
lead to an infinite loop in subsequent &rk_domain->iommus operations.

Cc: <stable@vger.kernel.org>
Fixes: 25c2325575cc ("iommu/rockchip: Add missing set_platform_dma_ops callback")
Signed-off-by: Simon Xue <xxm@rock-chips.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20250623020018.584802-1-xxm@rock-chips.com
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 22f74ba33a0e388a4f9d2ad7928e12c3e049a8da..e6bb3c784017cae2466a08a935b6732c06c6ae48 100644 (file)
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -1157,7 +1157,6 @@ static int rk_iommu_of_xlate(struct device *dev,
                return -ENOMEM;
 
        data->iommu = platform_get_drvdata(iommu_dev);
-       data->iommu->domain = &rk_identity_domain;
        dev_iommu_priv_set(dev, data);
 
        platform_device_put(iommu_dev);
@@ -1195,6 +1194,8 @@ static int rk_iommu_probe(struct platform_device *pdev)
        if (!iommu)
                return -ENOMEM;
 
+       iommu->domain = &rk_identity_domain;
+
        platform_set_drvdata(pdev, iommu);
        iommu->dev = dev;
        iommu->num_mmu = 0;