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* [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
@ 2020-06-19 22:43 Gustavo A. R. Silva
  2020-06-24  5:55 ` Vinod Koul
  0 siblings, 1 reply; 12+ messages in thread
From: Gustavo A. R. Silva @ 2020-06-19 22:43 UTC (permalink / raw)
  To: Dan Williams, Vinod Koul; +Cc: dmaengine, linux-kernel, Gustavo A. R. Silva

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

This code was detected with the help of Coccinelle and, audited and
fixed manually.

Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/dma/ti/k3-udma.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index 0d5fb154b8e2..411c54b86ba8 100644
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -2209,7 +2209,7 @@ udma_prep_slave_sg_pkt(struct udma_chan *uc, struct scatterlist *sgl,
 	u32 ring_id;
 	unsigned int i;
 
-	d = kzalloc(sizeof(*d) + sglen * sizeof(d->hwdesc[0]), GFP_NOWAIT);
+	d = kzalloc(struct_size(d, hwdesc, sglen), GFP_NOWAIT);
 	if (!d)
 		return NULL;
 
@@ -2525,7 +2525,7 @@ udma_prep_dma_cyclic_pkt(struct udma_chan *uc, dma_addr_t buf_addr,
 	if (period_len >= SZ_4M)
 		return NULL;
 
-	d = kzalloc(sizeof(*d) + periods * sizeof(d->hwdesc[0]), GFP_NOWAIT);
+	d = kzalloc(struct_size(d, hwdesc, periods), GFP_NOWAIT);
 	if (!d)
 		return NULL;
 
-- 
2.27.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
  2020-06-19 22:43 [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc() Gustavo A. R. Silva
@ 2020-06-24  5:55 ` Vinod Koul
  2020-06-24  5:56   ` Joe Perches
                     ` (2 more replies)
  0 siblings, 3 replies; 12+ messages in thread
From: Vinod Koul @ 2020-06-24  5:55 UTC (permalink / raw)
  To: Gustavo A. R. Silva, Peter Ujfalusi
  Cc: Dan Williams, dmaengine, linux-kernel, Gustavo A. R. Silva

On 19-06-20, 17:43, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes.
> 
> This code was detected with the help of Coccinelle and, audited and
> fixed manually.
> 
> Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>  drivers/dma/ti/k3-udma.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
> index 0d5fb154b8e2..411c54b86ba8 100644
> --- a/drivers/dma/ti/k3-udma.c
> +++ b/drivers/dma/ti/k3-udma.c
> @@ -2209,7 +2209,7 @@ udma_prep_slave_sg_pkt(struct udma_chan *uc, struct scatterlist *sgl,
>  	u32 ring_id;
>  	unsigned int i;
>  
> -	d = kzalloc(sizeof(*d) + sglen * sizeof(d->hwdesc[0]), GFP_NOWAIT);
> +	d = kzalloc(struct_size(d, hwdesc, sglen), GFP_NOWAIT);

struct_size() is a * b + c but here we need, a + b * c.. the trailing
struct is N times here..


>  	if (!d)
>  		return NULL;
>  
> @@ -2525,7 +2525,7 @@ udma_prep_dma_cyclic_pkt(struct udma_chan *uc, dma_addr_t buf_addr,
>  	if (period_len >= SZ_4M)
>  		return NULL;
>  
> -	d = kzalloc(sizeof(*d) + periods * sizeof(d->hwdesc[0]), GFP_NOWAIT);
> +	d = kzalloc(struct_size(d, hwdesc, periods), GFP_NOWAIT);
>  	if (!d)
>  		return NULL;
>  
> -- 
> 2.27.0

-- 
~Vinod

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
  2020-06-24  5:55 ` Vinod Koul
@ 2020-06-24  5:56   ` Joe Perches
  2020-06-24  7:27     ` Vinod Koul
  2020-06-24  9:14   ` Peter Ujfalusi
  2020-06-24 17:12   ` Gustavo A. R. Silva
  2 siblings, 1 reply; 12+ messages in thread
From: Joe Perches @ 2020-06-24  5:56 UTC (permalink / raw)
  To: Vinod Koul, Gustavo A. R. Silva, Peter Ujfalusi
  Cc: Dan Williams, dmaengine, linux-kernel, Gustavo A. R. Silva

On Wed, 2020-06-24 at 11:25 +0530, Vinod Koul wrote:
> On 19-06-20, 17:43, Gustavo A. R. Silva wrote:
> > Make use of the struct_size() helper instead of an open-coded version
> > in order to avoid any potential type mistakes.
> > 
> > This code was detected with the help of Coccinelle and, audited and
> > fixed manually.
> > 
> > Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83

Is this odd tag really useful?

> > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> > ---
> >  drivers/dma/ti/k3-udma.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
> > index 0d5fb154b8e2..411c54b86ba8 100644
> > --- a/drivers/dma/ti/k3-udma.c
> > +++ b/drivers/dma/ti/k3-udma.c
> > @@ -2209,7 +2209,7 @@ udma_prep_slave_sg_pkt(struct udma_chan *uc, struct scatterlist *sgl,
> >  	u32 ring_id;
> >  	unsigned int i;
> >  
> > -	d = kzalloc(sizeof(*d) + sglen * sizeof(d->hwdesc[0]), GFP_NOWAIT);
> > +	d = kzalloc(struct_size(d, hwdesc, sglen), GFP_NOWAIT);
> 
> struct_size() is a * b + c but here we need, a + b * c.. the trailing
> struct is N times here..
> 
> 
> >  	if (!d)
> >  		return NULL;
> >  
> > @@ -2525,7 +2525,7 @@ udma_prep_dma_cyclic_pkt(struct udma_chan *uc, dma_addr_t buf_addr,
> >  	if (period_len >= SZ_4M)
> >  		return NULL;
> >  
> > -	d = kzalloc(sizeof(*d) + periods * sizeof(d->hwdesc[0]), GFP_NOWAIT);
> > +	d = kzalloc(struct_size(d, hwdesc, periods), GFP_NOWAIT);
> >  	if (!d)
> >  		return NULL;
> >  
> > -- 
> > 2.27.0


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
  2020-06-24  5:56   ` Joe Perches
@ 2020-06-24  7:27     ` Vinod Koul
  0 siblings, 0 replies; 12+ messages in thread
From: Vinod Koul @ 2020-06-24  7:27 UTC (permalink / raw)
  To: Joe Perches
  Cc: Gustavo A. R. Silva, Peter Ujfalusi, Dan Williams, dmaengine,
	linux-kernel, Gustavo A. R. Silva

On 23-06-20, 22:56, Joe Perches wrote:
> On Wed, 2020-06-24 at 11:25 +0530, Vinod Koul wrote:
> > On 19-06-20, 17:43, Gustavo A. R. Silva wrote:
> > > Make use of the struct_size() helper instead of an open-coded version
> > > in order to avoid any potential type mistakes.
> > > 
> > > This code was detected with the help of Coccinelle and, audited and
> > > fixed manually.
> > > 
> > > Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
> 
> Is this odd tag really useful?

Not at all :)

-- 
~Vinod

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
  2020-06-24  5:55 ` Vinod Koul
  2020-06-24  5:56   ` Joe Perches
@ 2020-06-24  9:14   ` Peter Ujfalusi
  2020-06-24 17:12   ` Gustavo A. R. Silva
  2 siblings, 0 replies; 12+ messages in thread
From: Peter Ujfalusi @ 2020-06-24  9:14 UTC (permalink / raw)
  To: Vinod Koul, Gustavo A. R. Silva
  Cc: Dan Williams, dmaengine, linux-kernel, Gustavo A. R. Silva



On 24/06/2020 8.55, Vinod Koul wrote:
> On 19-06-20, 17:43, Gustavo A. R. Silva wrote:
>> Make use of the struct_size() helper instead of an open-coded version
>> in order to avoid any potential type mistakes.
>>
>> This code was detected with the help of Coccinelle and, audited and
>> fixed manually.
>>
>> Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>> ---
>>  drivers/dma/ti/k3-udma.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
>> index 0d5fb154b8e2..411c54b86ba8 100644
>> --- a/drivers/dma/ti/k3-udma.c
>> +++ b/drivers/dma/ti/k3-udma.c
>> @@ -2209,7 +2209,7 @@ udma_prep_slave_sg_pkt(struct udma_chan *uc, struct scatterlist *sgl,
>>  	u32 ring_id;
>>  	unsigned int i;
>>  
>> -	d = kzalloc(sizeof(*d) + sglen * sizeof(d->hwdesc[0]), GFP_NOWAIT);
>> +	d = kzalloc(struct_size(d, hwdesc, sglen), GFP_NOWAIT);
> 
> struct_size() is a * b + c but here we need, a + b * c.. the trailing
> struct is N times here..

Yes, that's correct.

> 
> 
>>  	if (!d)
>>  		return NULL;
>>  
>> @@ -2525,7 +2525,7 @@ udma_prep_dma_cyclic_pkt(struct udma_chan *uc, dma_addr_t buf_addr,
>>  	if (period_len >= SZ_4M)
>>  		return NULL;
>>  
>> -	d = kzalloc(sizeof(*d) + periods * sizeof(d->hwdesc[0]), GFP_NOWAIT);
>> +	d = kzalloc(struct_size(d, hwdesc, periods), GFP_NOWAIT);
>>  	if (!d)
>>  		return NULL;
>>  
>> -- 
>> 2.27.0
> 

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
  2020-06-24  5:55 ` Vinod Koul
  2020-06-24  5:56   ` Joe Perches
  2020-06-24  9:14   ` Peter Ujfalusi
@ 2020-06-24 17:12   ` Gustavo A. R. Silva
  2020-06-26  7:30     ` Peter Ujfalusi
  2 siblings, 1 reply; 12+ messages in thread
From: Gustavo A. R. Silva @ 2020-06-24 17:12 UTC (permalink / raw)
  To: Vinod Koul, Gustavo A. R. Silva, Peter Ujfalusi
  Cc: Dan Williams, dmaengine, linux-kernel

Hi Vinod,

On 6/24/20 00:55, Vinod Koul wrote:
> On 19-06-20, 17:43, Gustavo A. R. Silva wrote:
>> Make use of the struct_size() helper instead of an open-coded version
>> in order to avoid any potential type mistakes.
>>
>> This code was detected with the help of Coccinelle and, audited and
>> fixed manually.
>>
>> Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>> ---
>>  drivers/dma/ti/k3-udma.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
>> index 0d5fb154b8e2..411c54b86ba8 100644
>> --- a/drivers/dma/ti/k3-udma.c
>> +++ b/drivers/dma/ti/k3-udma.c
>> @@ -2209,7 +2209,7 @@ udma_prep_slave_sg_pkt(struct udma_chan *uc, struct scatterlist *sgl,
>>  	u32 ring_id;
>>  	unsigned int i;
>>  
>> -	d = kzalloc(sizeof(*d) + sglen * sizeof(d->hwdesc[0]), GFP_NOWAIT);
>> +	d = kzalloc(struct_size(d, hwdesc, sglen), GFP_NOWAIT);
> 
> struct_size() is a * b + c but here we need, a + b * c.. the trailing
> struct is N times here..
> 

struct_size() works exactly as expected in this case. :)
Please, see:

include/linux/overflow.h:314:
314 #define struct_size(p, member, count)                                   \
315         __ab_c_size(count,                                              \
316                     sizeof(*(p)->member) + __must_be_array((p)->member),\
317                     sizeof(*(p)))
318

Thanks
--
Gustavo

>>  	if (!d)
>>  		return NULL;
>>  
>> @@ -2525,7 +2525,7 @@ udma_prep_dma_cyclic_pkt(struct udma_chan *uc, dma_addr_t buf_addr,
>>  	if (period_len >= SZ_4M)
>>  		return NULL;
>>  
>> -	d = kzalloc(sizeof(*d) + periods * sizeof(d->hwdesc[0]), GFP_NOWAIT);
>> +	d = kzalloc(struct_size(d, hwdesc, periods), GFP_NOWAIT);
>>  	if (!d)
>>  		return NULL;
>>  
>> -- 
>> 2.27.0
> 

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
  2020-06-24 17:12   ` Gustavo A. R. Silva
@ 2020-06-26  7:30     ` Peter Ujfalusi
  2020-06-26 13:29       ` Gustavo A. R. Silva
  0 siblings, 1 reply; 12+ messages in thread
From: Peter Ujfalusi @ 2020-06-26  7:30 UTC (permalink / raw)
  To: Gustavo A. R. Silva, Vinod Koul, Gustavo A. R. Silva
  Cc: Dan Williams, dmaengine, linux-kernel



On 24/06/2020 20.12, Gustavo A. R. Silva wrote:
> Hi Vinod,
> 
> On 6/24/20 00:55, Vinod Koul wrote:
>> On 19-06-20, 17:43, Gustavo A. R. Silva wrote:
>>> Make use of the struct_size() helper instead of an open-coded version
>>> in order to avoid any potential type mistakes.
>>>
>>> This code was detected with the help of Coccinelle and, audited and
>>> fixed manually.
>>>
>>> Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
>>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>>> ---
>>>  drivers/dma/ti/k3-udma.c | 4 ++--
>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
>>> index 0d5fb154b8e2..411c54b86ba8 100644
>>> --- a/drivers/dma/ti/k3-udma.c
>>> +++ b/drivers/dma/ti/k3-udma.c
>>> @@ -2209,7 +2209,7 @@ udma_prep_slave_sg_pkt(struct udma_chan *uc, struct scatterlist *sgl,
>>>  	u32 ring_id;
>>>  	unsigned int i;
>>>  
>>> -	d = kzalloc(sizeof(*d) + sglen * sizeof(d->hwdesc[0]), GFP_NOWAIT);
>>> +	d = kzalloc(struct_size(d, hwdesc, sglen), GFP_NOWAIT);
>>
>> struct_size() is a * b + c but here we need, a + b * c.. the trailing
>> struct is N times here..
>>
> 
> struct_size() works exactly as expected in this case. :)
> Please, see:
> 
> include/linux/overflow.h:314:
> 314 #define struct_size(p, member, count)                                   \
> 315         __ab_c_size(count,                                              \
> 316                     sizeof(*(p)->member) + __must_be_array((p)->member),\
> 317                     sizeof(*(p)))

True, struct_size is for this sort of things.

Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>

While looking it up in include/linux/overflow.h I have noticed your
commit in linux-next, which adds flex_array_size()

The example in the commit message contradicts with what the helper
does imho. To be correct it should have been:

struct something {
	size_t count;
	struct foo items[];
};

- struct something *instance;
+ struct something instance;

- instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
+ instance.items = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
instance->count = count;
memcpy(instance->items, src, flex_array_size(instance, items, instance->count));

If I'm not mistaken..


> 
> Thanks
> --
> Gustavo
> 
>>>  	if (!d)
>>>  		return NULL;
>>>  
>>> @@ -2525,7 +2525,7 @@ udma_prep_dma_cyclic_pkt(struct udma_chan *uc, dma_addr_t buf_addr,
>>>  	if (period_len >= SZ_4M)
>>>  		return NULL;
>>>  
>>> -	d = kzalloc(sizeof(*d) + periods * sizeof(d->hwdesc[0]), GFP_NOWAIT);
>>> +	d = kzalloc(struct_size(d, hwdesc, periods), GFP_NOWAIT);
>>>  	if (!d)
>>>  		return NULL;
>>>  
>>> -- 
>>> 2.27.0
>>

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
  2020-06-26  7:30     ` Peter Ujfalusi
@ 2020-06-26 13:29       ` Gustavo A. R. Silva
  2020-06-29  6:43         ` Peter Ujfalusi
  0 siblings, 1 reply; 12+ messages in thread
From: Gustavo A. R. Silva @ 2020-06-26 13:29 UTC (permalink / raw)
  To: Peter Ujfalusi
  Cc: Gustavo A. R. Silva, Vinod Koul, Dan Williams, dmaengine, linux-kernel

Hi Peter,

Please, see my comments below...

On Fri, Jun 26, 2020 at 10:30:37AM +0300, Peter Ujfalusi wrote:
> 
> 
> On 24/06/2020 20.12, Gustavo A. R. Silva wrote:
> > Hi Vinod,
> > 
> > On 6/24/20 00:55, Vinod Koul wrote:
> >> On 19-06-20, 17:43, Gustavo A. R. Silva wrote:
> >>> Make use of the struct_size() helper instead of an open-coded version
> >>> in order to avoid any potential type mistakes.
> >>>
> >>> This code was detected with the help of Coccinelle and, audited and
> >>> fixed manually.
> >>>
> >>> Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
> >>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> >>> ---
> >>>  drivers/dma/ti/k3-udma.c | 4 ++--
> >>>  1 file changed, 2 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
> >>> index 0d5fb154b8e2..411c54b86ba8 100644
> >>> --- a/drivers/dma/ti/k3-udma.c
> >>> +++ b/drivers/dma/ti/k3-udma.c
> >>> @@ -2209,7 +2209,7 @@ udma_prep_slave_sg_pkt(struct udma_chan *uc, struct scatterlist *sgl,
> >>>  	u32 ring_id;
> >>>  	unsigned int i;
> >>>  
> >>> -	d = kzalloc(sizeof(*d) + sglen * sizeof(d->hwdesc[0]), GFP_NOWAIT);
> >>> +	d = kzalloc(struct_size(d, hwdesc, sglen), GFP_NOWAIT);
> >>
> >> struct_size() is a * b + c but here we need, a + b * c.. the trailing
> >> struct is N times here..
> >>
> > 
> > struct_size() works exactly as expected in this case. :)
> > Please, see:
> > 
> > include/linux/overflow.h:314:
> > 314 #define struct_size(p, member, count)                                   \
> > 315         __ab_c_size(count,                                              \
> > 316                     sizeof(*(p)->member) + __must_be_array((p)->member),\
> > 317                     sizeof(*(p)))
> 
> True, struct_size is for this sort of things.
> 
> Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> 
> While looking it up in include/linux/overflow.h I have noticed your
> commit in linux-next, which adds flex_array_size()
> 
> The example in the commit message contradicts with what the helper

There is no contradiction here.

> does imho. To be correct it should have been:
> 
> struct something {
> 	size_t count;
> 	struct foo items[];
> };
> 
> - struct something *instance;
> + struct something instance;
> 
> - instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
> + instance.items = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
> instance->count = count;
> memcpy(instance->items, src, flex_array_size(instance, items, instance->count));
> 

This is all wrong. Please, double check how struct_size() works.

Thanks
--
Gustavo

> >>>  	if (!d)
> >>>  		return NULL;
> >>>  
> >>> @@ -2525,7 +2525,7 @@ udma_prep_dma_cyclic_pkt(struct udma_chan *uc, dma_addr_t buf_addr,
> >>>  	if (period_len >= SZ_4M)
> >>>  		return NULL;
> >>>  
> >>> -	d = kzalloc(sizeof(*d) + periods * sizeof(d->hwdesc[0]), GFP_NOWAIT);
> >>> +	d = kzalloc(struct_size(d, hwdesc, periods), GFP_NOWAIT);
> >>>  	if (!d)
> >>>  		return NULL;
> >>>  
> >>> -- 
> >>> 2.27.0
> >>
> 
> - Péter
> 
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> 

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
  2020-06-26 13:29       ` Gustavo A. R. Silva
@ 2020-06-29  6:43         ` Peter Ujfalusi
  2020-07-10 18:25           ` Gustavo A. R. Silva
  0 siblings, 1 reply; 12+ messages in thread
From: Peter Ujfalusi @ 2020-06-29  6:43 UTC (permalink / raw)
  To: Gustavo A. R. Silva
  Cc: Gustavo A. R. Silva, Vinod Koul, Dan Williams, dmaengine, linux-kernel



On 26/06/2020 16.29, Gustavo A. R. Silva wrote:
> Hi Peter,
> 
> Please, see my comments below...
> 
> On Fri, Jun 26, 2020 at 10:30:37AM +0300, Peter Ujfalusi wrote:
>>
>>
>> On 24/06/2020 20.12, Gustavo A. R. Silva wrote:
>>> Hi Vinod,
>>>
>>> On 6/24/20 00:55, Vinod Koul wrote:
>>>> On 19-06-20, 17:43, Gustavo A. R. Silva wrote:
>>>>> Make use of the struct_size() helper instead of an open-coded version
>>>>> in order to avoid any potential type mistakes.
>>>>>
>>>>> This code was detected with the help of Coccinelle and, audited and
>>>>> fixed manually.
>>>>>
>>>>> Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
>>>>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
>>>>> ---
>>>>>  drivers/dma/ti/k3-udma.c | 4 ++--
>>>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
>>>>> index 0d5fb154b8e2..411c54b86ba8 100644
>>>>> --- a/drivers/dma/ti/k3-udma.c
>>>>> +++ b/drivers/dma/ti/k3-udma.c
>>>>> @@ -2209,7 +2209,7 @@ udma_prep_slave_sg_pkt(struct udma_chan *uc, struct scatterlist *sgl,
>>>>>  	u32 ring_id;
>>>>>  	unsigned int i;
>>>>>  
>>>>> -	d = kzalloc(sizeof(*d) + sglen * sizeof(d->hwdesc[0]), GFP_NOWAIT);
>>>>> +	d = kzalloc(struct_size(d, hwdesc, sglen), GFP_NOWAIT);
>>>>
>>>> struct_size() is a * b + c but here we need, a + b * c.. the trailing
>>>> struct is N times here..
>>>>
>>>
>>> struct_size() works exactly as expected in this case. :)
>>> Please, see:
>>>
>>> include/linux/overflow.h:314:
>>> 314 #define struct_size(p, member, count)                                   \
>>> 315         __ab_c_size(count,                                              \
>>> 316                     sizeof(*(p)->member) + __must_be_array((p)->member),\
>>> 317                     sizeof(*(p)))
>>
>> True, struct_size is for this sort of things.
>>
>> Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>>
>> While looking it up in include/linux/overflow.h I have noticed your
>> commit in linux-next, which adds flex_array_size()
>>
>> The example in the commit message contradicts with what the helper
> 
> There is no contradiction here.
> 
>> does imho. To be correct it should have been:
>>
>> struct something {
>> 	size_t count;
>> 	struct foo items[];
>> };
>>
>> - struct something *instance;
>> + struct something instance;
>>
>> - instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
>> + instance.items = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
>> instance->count = count;
>> memcpy(instance->items, src, flex_array_size(instance, items, instance->count));
>>
> 
> This is all wrong. Please, double check how struct_size() works.

Yes, I got it mixed up, I know how struct_size works... For some reason
I just overlooked it's use in the kmalloc().

> 
> Thanks
> --
> Gustavo
> 
>>>>>  	if (!d)
>>>>>  		return NULL;
>>>>>  
>>>>> @@ -2525,7 +2525,7 @@ udma_prep_dma_cyclic_pkt(struct udma_chan *uc, dma_addr_t buf_addr,
>>>>>  	if (period_len >= SZ_4M)
>>>>>  		return NULL;
>>>>>  
>>>>> -	d = kzalloc(sizeof(*d) + periods * sizeof(d->hwdesc[0]), GFP_NOWAIT);
>>>>> +	d = kzalloc(struct_size(d, hwdesc, periods), GFP_NOWAIT);
>>>>>  	if (!d)
>>>>>  		return NULL;
>>>>>  
>>>>> -- 
>>>>> 2.27.0
>>>>
>>
>> - Péter
>>
>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>>

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki


^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
  2020-06-29  6:43         ` Peter Ujfalusi
@ 2020-07-10 18:25           ` Gustavo A. R. Silva
  2020-07-15  6:21             ` Vinod Koul
  0 siblings, 1 reply; 12+ messages in thread
From: Gustavo A. R. Silva @ 2020-07-10 18:25 UTC (permalink / raw)
  To: Peter Ujfalusi
  Cc: Gustavo A. R. Silva, Vinod Koul, Dan Williams, dmaengine, linux-kernel

Hi all,

Friendly ping: who can take this, please?

Thanks
--
Gustavo

On Mon, Jun 29, 2020 at 09:43:26AM +0300, Peter Ujfalusi wrote:
> 
> 
> On 26/06/2020 16.29, Gustavo A. R. Silva wrote:
> > Hi Peter,
> > 
> > Please, see my comments below...
> > 
> > On Fri, Jun 26, 2020 at 10:30:37AM +0300, Peter Ujfalusi wrote:
> >>
> >>
> >> On 24/06/2020 20.12, Gustavo A. R. Silva wrote:
> >>> Hi Vinod,
> >>>
> >>> On 6/24/20 00:55, Vinod Koul wrote:
> >>>> On 19-06-20, 17:43, Gustavo A. R. Silva wrote:
> >>>>> Make use of the struct_size() helper instead of an open-coded version
> >>>>> in order to avoid any potential type mistakes.
> >>>>>
> >>>>> This code was detected with the help of Coccinelle and, audited and
> >>>>> fixed manually.
> >>>>>
> >>>>> Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
> >>>>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> >>>>> ---
> >>>>>  drivers/dma/ti/k3-udma.c | 4 ++--
> >>>>>  1 file changed, 2 insertions(+), 2 deletions(-)
> >>>>>
> >>>>> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
> >>>>> index 0d5fb154b8e2..411c54b86ba8 100644
> >>>>> --- a/drivers/dma/ti/k3-udma.c
> >>>>> +++ b/drivers/dma/ti/k3-udma.c
> >>>>> @@ -2209,7 +2209,7 @@ udma_prep_slave_sg_pkt(struct udma_chan *uc, struct scatterlist *sgl,
> >>>>>  	u32 ring_id;
> >>>>>  	unsigned int i;
> >>>>>  
> >>>>> -	d = kzalloc(sizeof(*d) + sglen * sizeof(d->hwdesc[0]), GFP_NOWAIT);
> >>>>> +	d = kzalloc(struct_size(d, hwdesc, sglen), GFP_NOWAIT);
> >>>>
> >>>> struct_size() is a * b + c but here we need, a + b * c.. the trailing
> >>>> struct is N times here..
> >>>>
> >>>
> >>> struct_size() works exactly as expected in this case. :)
> >>> Please, see:
> >>>
> >>> include/linux/overflow.h:314:
> >>> 314 #define struct_size(p, member, count)                                   \
> >>> 315         __ab_c_size(count,                                              \
> >>> 316                     sizeof(*(p)->member) + __must_be_array((p)->member),\
> >>> 317                     sizeof(*(p)))
> >>
> >> True, struct_size is for this sort of things.
> >>
> >> Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> >>
> >> While looking it up in include/linux/overflow.h I have noticed your
> >> commit in linux-next, which adds flex_array_size()
> >>
> >> The example in the commit message contradicts with what the helper
> > 
> > There is no contradiction here.
> > 
> >> does imho. To be correct it should have been:
> >>
> >> struct something {
> >> 	size_t count;
> >> 	struct foo items[];
> >> };
> >>
> >> - struct something *instance;
> >> + struct something instance;
> >>
> >> - instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
> >> + instance.items = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
> >> instance->count = count;
> >> memcpy(instance->items, src, flex_array_size(instance, items, instance->count));
> >>
> > 
> > This is all wrong. Please, double check how struct_size() works.
> 
> Yes, I got it mixed up, I know how struct_size works... For some reason
> I just overlooked it's use in the kmalloc().
> 
> > 
> > Thanks
> > --
> > Gustavo
> > 
> >>>>>  	if (!d)
> >>>>>  		return NULL;
> >>>>>  
> >>>>> @@ -2525,7 +2525,7 @@ udma_prep_dma_cyclic_pkt(struct udma_chan *uc, dma_addr_t buf_addr,
> >>>>>  	if (period_len >= SZ_4M)
> >>>>>  		return NULL;
> >>>>>  
> >>>>> -	d = kzalloc(sizeof(*d) + periods * sizeof(d->hwdesc[0]), GFP_NOWAIT);
> >>>>> +	d = kzalloc(struct_size(d, hwdesc, periods), GFP_NOWAIT);
> >>>>>  	if (!d)
> >>>>>  		return NULL;
> >>>>>  
> >>>>> -- 
> >>>>> 2.27.0
> >>>>
> >>
> >> - Péter
> >>
> >> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> >>
> 
> - Péter
> 
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> 

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
  2020-07-10 18:25           ` Gustavo A. R. Silva
@ 2020-07-15  6:21             ` Vinod Koul
  2020-07-15 14:06               ` Gustavo A. R. Silva
  0 siblings, 1 reply; 12+ messages in thread
From: Vinod Koul @ 2020-07-15  6:21 UTC (permalink / raw)
  To: Gustavo A. R. Silva
  Cc: Peter Ujfalusi, Gustavo A. R. Silva, Dan Williams, dmaengine,
	linux-kernel

On 10-07-20, 13:25, Gustavo A. R. Silva wrote:
> Hi all,
> 
> Friendly ping: who can take this, please?

Applied now

-- 
~Vinod

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc()
  2020-07-15  6:21             ` Vinod Koul
@ 2020-07-15 14:06               ` Gustavo A. R. Silva
  0 siblings, 0 replies; 12+ messages in thread
From: Gustavo A. R. Silva @ 2020-07-15 14:06 UTC (permalink / raw)
  To: Vinod Koul, Gustavo A. R. Silva
  Cc: Peter Ujfalusi, Dan Williams, dmaengine, linux-kernel



On 7/15/20 01:21, Vinod Koul wrote:
> On 10-07-20, 13:25, Gustavo A. R. Silva wrote:
>> Hi all,
>>
>> Friendly ping: who can take this, please?
> 
> Applied now
> 

Thanks, Vinod.

--
Gustavo

^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, back to index

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-19 22:43 [PATCH][next] dmaengine: ti: k3-udma: Use struct_size() in kzalloc() Gustavo A. R. Silva
2020-06-24  5:55 ` Vinod Koul
2020-06-24  5:56   ` Joe Perches
2020-06-24  7:27     ` Vinod Koul
2020-06-24  9:14   ` Peter Ujfalusi
2020-06-24 17:12   ` Gustavo A. R. Silva
2020-06-26  7:30     ` Peter Ujfalusi
2020-06-26 13:29       ` Gustavo A. R. Silva
2020-06-29  6:43         ` Peter Ujfalusi
2020-07-10 18:25           ` Gustavo A. R. Silva
2020-07-15  6:21             ` Vinod Koul
2020-07-15 14:06               ` Gustavo A. R. Silva

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