| Message ID | 1502187962-16861-1-git-send-email-asavkov@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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.murphy@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 <asavkov@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) { >
[+ Joerg] On Tue, Aug 08, 2017 at 11:37:40AM +0100, Robin Murphy wrote: > 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.murphy@arm.com> > > Thanks for fixing it up, and sorry for failing to document the > unfortunately subtle logic in the first place! Well, I was the one that messed it up: Acked-by: Will Deacon <will.deacon@arm.com> Joerg, can you pick this up as a fix for 4.13, please? Will > > Signed-off-by: Artem Savkov <asavkov@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) { > > >
On 08/08/2017 04:21 AM, Will Deacon wrote: > [+ Joerg] > > On Tue, Aug 08, 2017 at 11:37:40AM +0100, Robin Murphy wrote: >> 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.murphy@arm.com> >> >> Thanks for fixing it up, and sorry for failing to document the >> unfortunately subtle logic in the first place! > > Well, I was the one that messed it up: > > Acked-by: Will Deacon <will.deacon@arm.com> > > Joerg, can you pick this up as a fix for 4.13, please? I hit the Oops as well. This patch fixes it for me on a Cavium CN88xx system, so: Acked-by: David Daney <david.daney@cavium.com> Thanks for working on this. > > Will > >>> Signed-off-by: Artem Savkov <asavkov@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) { >>> >> > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
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) {
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. Signed-off-by: Artem Savkov <asavkov@redhat.com> --- drivers/iommu/arm-smmu.c | 7 +++++++ 1 file changed, 7 insertions(+)