From 2062f9fb6445451b189595e295765c69f43bc12e Mon Sep 17 00:00:00 2001 From: Oleksandr Tyshchenko Date: Wed, 8 Feb 2023 17:36:49 +0200 Subject: [PATCH] xen/grant-dma-iommu: Implement a dummy probe_device() callback Update stub IOMMU driver (which main purpose is to reuse generic IOMMU device-tree bindings by Xen grant DMA-mapping layer on Arm) according to the recent changes done in the following commit 57365a04c921 ("iommu: Move bus setup to IOMMU device registration"). With probe_device() callback being called during IOMMU device registration, the uninitialized callback just leads to the "kernel NULL pointer dereference" issue during boot. Fix that by adding a dummy callback. Looks like the release_device() callback is not mandatory to be implemented as IOMMU framework makes sure that callback is initialized before dereferencing. Reported-by: Viresh Kumar Fixes: 57365a04c921 ("iommu: Move bus setup to IOMMU device registration") Signed-off-by: Oleksandr Tyshchenko Tested-by: Viresh Kumar Reviewed-by: Stefano Stabellini Link: https://lore.kernel.org/r/20230208153649.3604857-1-olekstysh@gmail.com Signed-off-by: Juergen Gross --- drivers/xen/grant-dma-iommu.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/xen/grant-dma-iommu.c b/drivers/xen/grant-dma-iommu.c index 16b8bc0c0b33..6a9fe02c6bfc 100644 --- a/drivers/xen/grant-dma-iommu.c +++ b/drivers/xen/grant-dma-iommu.c @@ -16,8 +16,15 @@ struct grant_dma_iommu_device { struct iommu_device iommu; }; -/* Nothing is really needed here */ -static const struct iommu_ops grant_dma_iommu_ops; +static struct iommu_device *grant_dma_iommu_probe_device(struct device *dev) +{ + return ERR_PTR(-ENODEV); +} + +/* Nothing is really needed here except a dummy probe_device callback */ +static const struct iommu_ops grant_dma_iommu_ops = { + .probe_device = grant_dma_iommu_probe_device, +}; static const struct of_device_id grant_dma_iommu_of_match[] = { { .compatible = "xen,grant-dma" },