On 08/08/17 11:26, Artem Savkov wrote: > Commit c54451a "iommu/arm-smmu: Fix the error path in arm_smmu_add_device" > removed fwspec assignment in legacy_binding path as redundant which is > wrong. It needs to be updated after fwspec initialisation in > arm_smmu_register_legacy_master() as it is dereferenced later. Without > this there is a NULL-pointer dereference panic during boot on some hosts.
Reviewed-by: Robin Murphy <robin.mur...@arm.com> Thanks for fixing it up, and sorry for failing to document the unfortunately subtle logic in the first place! Robin. > Signed-off-by: Artem Savkov <asav...@redhat.com> > --- > drivers/iommu/arm-smmu.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index b97188a..2d80fa8 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -1519,6 +1519,13 @@ static int arm_smmu_add_device(struct device *dev) > > if (using_legacy_binding) { > ret = arm_smmu_register_legacy_master(dev, &smmu); > + > + /* > + * If dev->iommu_fwspec is initally NULL, > arm_smmu_register_legacy_master() > + * will allocate/initialise a new one. Thus we need to update > fwspec for > + * later use. > + */ > + fwspec = dev->iommu_fwspec; > if (ret) > goto out_free; > } else if (fwspec && fwspec->ops == &arm_smmu_ops) { >