[PATCH RESEND] arm: dma-mapping: Fix mapping size value

[PATCH RESEND] arm: dma-mapping: Fix mapping size value

[Ritesh Harjani]

Previous patch message got corrupted by my mail-server (copy-paste)
So resending it.
 
[history]: http://www.spinics.net/lists/arm-kernel/msg323904.html

Ritesh Harjani (1):
  arm: dma-mapping: Fix mapping size value

 arch/arm/mm/dma-mapping.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
1.8.1.3

[PATCH] arm: dma-mapping: Fix mapping size value

[Ritesh Harjani]

68efd7d2fb("arm: dma-mapping: remove order parameter from
arm_iommu_create_mapping()") is causing kernel panic
because it wrongly sets the value of mapping->size:

Unable to handle kernel NULL pointer dereference at virtual
address 000000a0
pgd = e7a84000
[000000a0] *pgd=00000000
...
PC is at bitmap_clear+0x48/0xd0
LR is at __iommu_remove_mapping+0x130/0x164

Fix it by correcting mapping->size value.

Signed-off-by: Ritesh Harjani <ritesh.harjani-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Acked-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
---
 arch/arm/mm/dma-mapping.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index f62aa06..6b00be1 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1963,8 +1963,8 @@ arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size)
 	mapping->nr_bitmaps = 1;
 	mapping->extensions = extensions;
 	mapping->base = base;
-	mapping->size = bitmap_size << PAGE_SHIFT;
 	mapping->bits = BITS_PER_BYTE * bitmap_size;
+	mapping->size = mapping->bits << PAGE_SHIFT;
 
 	spin_lock_init(&mapping->lock);
 
-- 
1.8.1.3

Re: [PATCH] arm: dma-mapping: Fix mapping size value

[Will Deacon]

On Mon, Apr 21, 2014 at 07:47:27AM +0100, Ritesh Harjani wrote:
> 68efd7d2fb("arm: dma-mapping: remove order parameter from
> arm_iommu_create_mapping()") is causing kernel panic
> because it wrongly sets the value of mapping->size:
> 
> Unable to handle kernel NULL pointer dereference at virtual
> address 000000a0
> pgd = e7a84000
> [000000a0] *pgd=00000000
> ...
> PC is at bitmap_clear+0x48/0xd0
> LR is at __iommu_remove_mapping+0x130/0x164
> 
> Fix it by correcting mapping->size value.
> 
> Signed-off-by: Ritesh Harjani <ritesh.harjani-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Acked-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
> ---
>  arch/arm/mm/dma-mapping.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index f62aa06..6b00be1 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -1963,8 +1963,8 @@ arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size)
>  	mapping->nr_bitmaps = 1;
>  	mapping->extensions = extensions;
>  	mapping->base = base;
> -	mapping->size = bitmap_size << PAGE_SHIFT;
>  	mapping->bits = BITS_PER_BYTE * bitmap_size;
> +	mapping->size = mapping->bits << PAGE_SHIFT;

Ok, but given that mapping->size is derived from mapping->bits, do we really
need both of these fields in struct dma_iommu_mapping?

Will

Re: [PATCH] arm: dma-mapping: Fix mapping size value

[Marek Szyprowski]

Hello,

On 2014-04-22 10:53, Will Deacon wrote:
> On Mon, Apr 21, 2014 at 07:47:27AM +0100, Ritesh Harjani wrote:
> > 68efd7d2fb("arm: dma-mapping: remove order parameter from
> > arm_iommu_create_mapping()") is causing kernel panic
> > because it wrongly sets the value of mapping->size:
> >
> > Unable to handle kernel NULL pointer dereference at virtual
> > address 000000a0
> > pgd = e7a84000
> > [000000a0] *pgd=00000000
> > ...
> > PC is at bitmap_clear+0x48/0xd0
> > LR is at __iommu_remove_mapping+0x130/0x164
> >
> > Fix it by correcting mapping->size value.
> >
> > Signed-off-by: Ritesh Harjani <ritesh.harjani-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > Acked-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
> > ---
> >  arch/arm/mm/dma-mapping.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> > index f62aa06..6b00be1 100644
> > --- a/arch/arm/mm/dma-mapping.c
> > +++ b/arch/arm/mm/dma-mapping.c
> > @@ -1963,8 +1963,8 @@ arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size)
> >  	mapping->nr_bitmaps = 1;
> >  	mapping->extensions = extensions;
> >  	mapping->base = base;
> > -	mapping->size = bitmap_size << PAGE_SHIFT;
> >  	mapping->bits = BITS_PER_BYTE * bitmap_size;
> > +	mapping->size = mapping->bits << PAGE_SHIFT;
>
> Ok, but given that mapping->size is derived from mapping->bits, do we really
> need both of these fields in struct dma_iommu_mapping?

You are right. I didn't notice this while I was refactoring the code. 
Ritesh,
could you update your patch and simply replace all references of 
mapping->size
with (mapping->bits << PAGE_SHIFT), probably with some temporary variable to
make the code easier to understand? I've didn't apply your patch yet.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH] arm: dma-mapping: Fix mapping size value

[Laurent Pinchart]

Hi Marek,

On Wednesday 23 April 2014 10:53:24 Marek Szyprowski wrote:
> On 2014-04-22 10:53, Will Deacon wrote:
> > On Mon, Apr 21, 2014 at 07:47:27AM +0100, Ritesh Harjani wrote:
> > > 68efd7d2fb("arm: dma-mapping: remove order parameter from
> > > arm_iommu_create_mapping()") is causing kernel panic
> > > because it wrongly sets the value of mapping->size:
> > > 
> > > Unable to handle kernel NULL pointer dereference at virtual
> > > address 000000a0
> > > pgd = e7a84000
> > > [000000a0] *pgd=00000000
> > > ...
> > > PC is at bitmap_clear+0x48/0xd0
> > > LR is at __iommu_remove_mapping+0x130/0x164
> > > 
> > > Fix it by correcting mapping->size value.
> > > 
> > > Signed-off-by: Ritesh Harjani <ritesh.harjani-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > > Acked-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
> > > ---
> > > 
> > >  arch/arm/mm/dma-mapping.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> > > index f62aa06..6b00be1 100644
> > > --- a/arch/arm/mm/dma-mapping.c
> > > +++ b/arch/arm/mm/dma-mapping.c
> > > @@ -1963,8 +1963,8 @@ arm_iommu_create_mapping(struct bus_type *bus,
> > > dma_addr_t base, size_t size)> > 
> > >  	mapping->nr_bitmaps = 1;
> > >  	mapping->extensions = extensions;
> > >  	mapping->base = base;
> > > 
> > > -	mapping->size = bitmap_size << PAGE_SHIFT;
> > > 
> > >  	mapping->bits = BITS_PER_BYTE * bitmap_size;
> > > 
> > > +	mapping->size = mapping->bits << PAGE_SHIFT;
> > 
> > Ok, but given that mapping->size is derived from mapping->bits, do we
> > really need both of these fields in struct dma_iommu_mapping?
> 
> You are right. I didn't notice this while I was refactoring the code.
> Ritesh, could you update your patch and simply replace all references of
> mapping->size with (mapping->bits << PAGE_SHIFT), probably with some
> temporary variable to make the code easier to understand? I've didn't apply
> your patch yet.

As this patch fixes a v3.15 regression, shouldn't it be applied as-is and 
ASAP, with the cleanup that removes mapping->size coming in a later, less 
urgent patch ?

-- 
Regards,

Laurent Pinchart

Re: [PATCH] arm: dma-mapping: Fix mapping size value

[Ritesh Harjani]

Hi Marek/Will

On Wed, Apr 23, 2014 at 3:00 PM, Laurent Pinchart
<laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org> wrote:
> Hi Marek,
>
> On Wednesday 23 April 2014 10:53:24 Marek Szyprowski wrote:
>> On 2014-04-22 10:53, Will Deacon wrote:
>> > On Mon, Apr 21, 2014 at 07:47:27AM +0100, Ritesh Harjani wrote:
>> > > 68efd7d2fb("arm: dma-mapping: remove order parameter from
>> > > arm_iommu_create_mapping()") is causing kernel panic
>> > > because it wrongly sets the value of mapping->size:
>> > >
>> > > Unable to handle kernel NULL pointer dereference at virtual
>> > > address 000000a0
>> > > pgd = e7a84000
>> > > [000000a0] *pgd=00000000
>> > > ...
>> > > PC is at bitmap_clear+0x48/0xd0
>> > > LR is at __iommu_remove_mapping+0x130/0x164
>> > >
>> > > Fix it by correcting mapping->size value.
>> > >
>> > > Signed-off-by: Ritesh Harjani <ritesh.harjani-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> > > Acked-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
>> > > ---
>> > >
>> > >  arch/arm/mm/dma-mapping.c | 2 +-
>> > >  1 file changed, 1 insertion(+), 1 deletion(-)
>> > >
>> > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
>> > > index f62aa06..6b00be1 100644
>> > > --- a/arch/arm/mm/dma-mapping.c
>> > > +++ b/arch/arm/mm/dma-mapping.c
>> > > @@ -1963,8 +1963,8 @@ arm_iommu_create_mapping(struct bus_type *bus,
>> > > dma_addr_t base, size_t size)> >
>> > >   mapping->nr_bitmaps = 1;
>> > >   mapping->extensions = extensions;
>> > >   mapping->base = base;
>> > >
>> > > - mapping->size = bitmap_size << PAGE_SHIFT;
>> > >
>> > >   mapping->bits = BITS_PER_BYTE * bitmap_size;
>> > >
>> > > + mapping->size = mapping->bits << PAGE_SHIFT;
>> >
>> > Ok, but given that mapping->size is derived from mapping->bits, do we
>> > really need both of these fields in struct dma_iommu_mapping?
>>
>> You are right. I didn't notice this while I was refactoring the code.
>> Ritesh, could you update your patch and simply replace all references of
>> mapping->size with (mapping->bits << PAGE_SHIFT), probably with some
>> temporary variable to make the code easier to understand? I've didn't apply
>> your patch yet.
>
> As this patch fixes a v3.15 regression, shouldn't it be applied as-is and
> ASAP, with the cleanup that removes mapping->size coming in a later, less
> urgent patch ?

I agree with Laurent. Anyway this cleanup can be taken care when we will be
doing refactoring of common code to lib/iommu-helper.c.

Anyways, if you still insist I can prepare and submit the patch. Let me know
again on this.

>
> --
> Regards,
>
> Laurent Pinchart
>

Thanks
Ritesh

Re: [PATCH] arm: dma-mapping: Fix mapping size value

[Marek Szyprowski]

Hello,

On 2014-04-23 12:04, Ritesh Harjani wrote:
> Hi Marek/Will
>
> On Wed, Apr 23, 2014 at 3:00 PM, Laurent Pinchart
> <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org> wrote:
> > Hi Marek,
> >
> > On Wednesday 23 April 2014 10:53:24 Marek Szyprowski wrote:
> >> On 2014-04-22 10:53, Will Deacon wrote:
> >> > On Mon, Apr 21, 2014 at 07:47:27AM +0100, Ritesh Harjani wrote:
> >> > > 68efd7d2fb("arm: dma-mapping: remove order parameter from
> >> > > arm_iommu_create_mapping()") is causing kernel panic
> >> > > because it wrongly sets the value of mapping->size:
> >> > >
> >> > > Unable to handle kernel NULL pointer dereference at virtual
> >> > > address 000000a0
> >> > > pgd = e7a84000
> >> > > [000000a0] *pgd=00000000
> >> > > ...
> >> > > PC is at bitmap_clear+0x48/0xd0
> >> > > LR is at __iommu_remove_mapping+0x130/0x164
> >> > >
> >> > > Fix it by correcting mapping->size value.
> >> > >
> >> > > Signed-off-by: Ritesh Harjani <ritesh.harjani-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> >> > > Acked-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
> >> > > ---
> >> > >
> >> > >  arch/arm/mm/dma-mapping.c | 2 +-
> >> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> >> > >
> >> > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> >> > > index f62aa06..6b00be1 100644
> >> > > --- a/arch/arm/mm/dma-mapping.c
> >> > > +++ b/arch/arm/mm/dma-mapping.c
> >> > > @@ -1963,8 +1963,8 @@ arm_iommu_create_mapping(struct bus_type *bus,
> >> > > dma_addr_t base, size_t size)> >
> >> > >   mapping->nr_bitmaps = 1;
> >> > >   mapping->extensions = extensions;
> >> > >   mapping->base = base;
> >> > >
> >> > > - mapping->size = bitmap_size << PAGE_SHIFT;
> >> > >
> >> > >   mapping->bits = BITS_PER_BYTE * bitmap_size;
> >> > >
> >> > > + mapping->size = mapping->bits << PAGE_SHIFT;
> >> >
> >> > Ok, but given that mapping->size is derived from mapping->bits, do we
> >> > really need both of these fields in struct dma_iommu_mapping?
> >>
> >> You are right. I didn't notice this while I was refactoring the code.
> >> Ritesh, could you update your patch and simply replace all references of
> >> mapping->size with (mapping->bits << PAGE_SHIFT), probably with some
> >> temporary variable to make the code easier to understand? I've didn't apply
> >> your patch yet.
> >
> > As this patch fixes a v3.15 regression, shouldn't it be applied as-is and
> > ASAP, with the cleanup that removes mapping->size coming in a later, less
> > urgent patch ?
>
> I agree with Laurent. Anyway this cleanup can be taken care when we will be
> doing refactoring of common code to lib/iommu-helper.c.
>
> Anyways, if you still insist I can prepare and submit the patch. Let me know
> again on this.

Ok, I've merged the patch as is and I will send pull request soon.
Please include the above discussed cleanup while refactoring common code 
to lib.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH] arm: dma-mapping: Fix mapping size value

[Ritesh Harjani]

Ok thanks Marek,

I was about to send a new patch (as I had now got hold of my system).
Anyways, I will add this discussion of cleaning up this variable in my
to-do list.


Thanks
Ritesh

On Wed, Apr 23, 2014 at 6:47 PM, Marek Szyprowski
<m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> wrote:
> Hello,
>
>
> On 2014-04-23 12:04, Ritesh Harjani wrote:
>>
>> Hi Marek/Will
>>
>> On Wed, Apr 23, 2014 at 3:00 PM, Laurent Pinchart
>> <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org> wrote:
>> > Hi Marek,
>> >
>> > On Wednesday 23 April 2014 10:53:24 Marek Szyprowski wrote:
>> >> On 2014-04-22 10:53, Will Deacon wrote:
>> >> > On Mon, Apr 21, 2014 at 07:47:27AM +0100, Ritesh Harjani wrote:
>> >> > > 68efd7d2fb("arm: dma-mapping: remove order parameter from
>> >> > > arm_iommu_create_mapping()") is causing kernel panic
>> >> > > because it wrongly sets the value of mapping->size:
>> >> > >
>> >> > > Unable to handle kernel NULL pointer dereference at virtual
>> >> > > address 000000a0
>> >> > > pgd = e7a84000
>> >> > > [000000a0] *pgd=00000000
>> >> > > ...
>> >> > > PC is at bitmap_clear+0x48/0xd0
>> >> > > LR is at __iommu_remove_mapping+0x130/0x164
>> >> > >
>> >> > > Fix it by correcting mapping->size value.
>> >> > >
>> >> > > Signed-off-by: Ritesh Harjani <ritesh.harjani-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> >> > > Acked-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
>> >> > > ---
>> >> > >
>> >> > >  arch/arm/mm/dma-mapping.c | 2 +-
>> >> > >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >> > >
>> >> > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
>> >> > > index f62aa06..6b00be1 100644
>> >> > > --- a/arch/arm/mm/dma-mapping.c
>> >> > > +++ b/arch/arm/mm/dma-mapping.c
>> >> > > @@ -1963,8 +1963,8 @@ arm_iommu_create_mapping(struct bus_type
>> >> > > *bus,
>> >> > > dma_addr_t base, size_t size)> >
>> >> > >   mapping->nr_bitmaps = 1;
>> >> > >   mapping->extensions = extensions;
>> >> > >   mapping->base = base;
>> >> > >
>> >> > > - mapping->size = bitmap_size << PAGE_SHIFT;
>> >> > >
>> >> > >   mapping->bits = BITS_PER_BYTE * bitmap_size;
>> >> > >
>> >> > > + mapping->size = mapping->bits << PAGE_SHIFT;
>> >> >
>> >> > Ok, but given that mapping->size is derived from mapping->bits, do we
>> >> > really need both of these fields in struct dma_iommu_mapping?
>> >>
>> >> You are right. I didn't notice this while I was refactoring the code.
>> >> Ritesh, could you update your patch and simply replace all references
>> >> of
>> >> mapping->size with (mapping->bits << PAGE_SHIFT), probably with some
>> >> temporary variable to make the code easier to understand? I've didn't
>> >> apply
>> >> your patch yet.
>> >
>> > As this patch fixes a v3.15 regression, shouldn't it be applied as-is
>> > and
>> > ASAP, with the cleanup that removes mapping->size coming in a later,
>> > less
>> > urgent patch ?
>>
>> I agree with Laurent. Anyway this cleanup can be taken care when we will
>> be
>> doing refactoring of common code to lib/iommu-helper.c.
>>
>> Anyways, if you still insist I can prepare and submit the patch. Let me
>> know
>> again on this.
>
>
> Ok, I've merged the patch as is and I will send pull request soon.
> Please include the above discussed cleanup while refactoring common code to
> lib.
>
>
> Best regards
> --
> Marek Szyprowski, PhD
> Samsung R&D Institute Poland
>

Re: [PATCH] arm: dma-mapping: Fix mapping size value

[Marek Szyprowski]

Hello,

On 2014-04-21 08:47, Ritesh Harjani wrote:
> 68efd7d2fb("arm: dma-mapping: remove order parameter from
> arm_iommu_create_mapping()") is causing kernel panic
> because it wrongly sets the value of mapping->size:
>
> Unable to handle kernel NULL pointer dereference at virtual
> address 000000a0
> pgd = e7a84000
> [000000a0] *pgd=00000000
> ...
> PC is at bitmap_clear+0x48/0xd0
> LR is at __iommu_remove_mapping+0x130/0x164
>
> Fix it by correcting mapping->size value.
>
> Signed-off-by: Ritesh Harjani <ritesh.harjani-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Acked-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>

Thanks for spotting this issue! I'm really sorry for introducing it. I 
will push it to the fixes branch asap.

> ---
>   arch/arm/mm/dma-mapping.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index f62aa06..6b00be1 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -1963,8 +1963,8 @@ arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size)
>   	mapping->nr_bitmaps = 1;
>   	mapping->extensions = extensions;
>   	mapping->base = base;
> -	mapping->size = bitmap_size << PAGE_SHIFT;
>   	mapping->bits = BITS_PER_BYTE * bitmap_size;
> +	mapping->size = mapping->bits << PAGE_SHIFT;
>   
>   	spin_lock_init(&mapping->lock);

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland