This is a note to let you know that I've just added the patch titled
xen/grant-dma-iommu: Implement a dummy probe_device() callback
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-grant-dma-iommu-implement-a-dummy-probe_device-c.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 3031e29653e6d838095f4f0116fdd0749b0fb2fc
Author: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
Date: Wed Feb 8 17:36:49 2023 +0200
xen/grant-dma-iommu: Implement a dummy probe_device() callback
[ Upstream commit 2062f9fb6445451b189595e295765c69f43bc12e ]
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 <viresh.kumar@xxxxxxxxxx>
Fixes: 57365a04c921 ("iommu: Move bus setup to IOMMU device registration")
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
Tested-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230208153649.3604857-1-olekstysh@xxxxxxxxx
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/xen/grant-dma-iommu.c b/drivers/xen/grant-dma-iommu.c
index 16b8bc0c0b33d..6a9fe02c6bfcc 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" },
