| Message ID | 20230208153649.3604857-1-olekstysh@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 2062f9fb6445451b189595e295765c69f43bc12e |
| Headers | show |
| Series | xen/grant-dma-iommu: Implement a dummy probe_device() callback | expand |
On 08-02-23, 17:36, Oleksandr Tyshchenko wrote: > From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> > > 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@linaro.org> > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> > --- > drivers/xen/grant-dma-iommu.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) Tested-by: Viresh Kumar <viresh.kumar@linaro.org>
On Wed, 8 Feb 2023, Oleksandr Tyshchenko wrote: > From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> > > 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@linaro.org> > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > --- > 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" }, > -- > 2.34.1 >
On 08.02.23 16:36, Oleksandr Tyshchenko wrote: > From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> > > 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@linaro.org> > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Pushed-to: xen/tip.git for-linus-6.3 Juergen
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" },