Re: [PATCH] xen/grant-dma-iommu: Implement a dummy probe_device() callback

[Viresh Kumar <viresh.kumar@xxxxxxxxxx>]

On 08-02-23, 17:36, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> 
> 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>
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> ---
>  drivers/xen/grant-dma-iommu.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)

Tested-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>

-- 
viresh