Re: [PATCH v2] iommu/arm-smmu: fix null-pointer dereference in arm_smmu_add_device

[David Daney]

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 

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 

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 

Thanks for working on this.





Will


Signed-off-by: Artem Savkov 
---
  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, );
+
+   /*
+* 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 == _smmu_ops) {





___
linux-arm-kernel mailing list
linux-arm-ker...@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel



___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH v2] iommu/arm-smmu: fix null-pointer dereference in arm_smmu_add_device

[Will Deacon]

[+ 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 
> 
> 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 

Joerg, can you pick this up as a fix for 4.13, please?

Will

> > Signed-off-by: Artem Savkov 
> > ---
> >  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, );
> > +
> > +   /*
> > +* 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 == _smmu_ops) {
> > 
> 
___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH v2] iommu/arm-smmu: fix null-pointer dereference in arm_smmu_add_device

[Robin Murphy]

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 

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 
> ---
>  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, );
> +
> + /*
> +  * 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 == _smmu_ops) {
> 

___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

[PATCH v2] iommu/arm-smmu: fix null-pointer dereference in arm_smmu_add_device

[Artem Savkov]

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 
---
 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, );
+
+   /*
+* 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 == _smmu_ops) {
-- 
2.7.5

___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu