* [PATCH] omapfb: Use devm_kcalloc() in vrfb_probe()
@ 2017-04-26 9:20 ` SF Markus Elfring
0 siblings, 0 replies; 8+ messages in thread
From: SF Markus Elfring @ 2017-04-26 9:20 UTC (permalink / raw)
To: linux-fbdev, linux-omap, Bartlomiej Zolnierkiewicz, Tomi Valkeinen
Cc: LKML, kernel-janitors
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Wed, 26 Apr 2017 11:08:30 +0200
* A multiplication for the size determination of a memory allocation
indicated that an array data structure should be processed.
Thus use the corresponding function "devm_kcalloc".
* Replace the specification of a data structure by a pointer dereference
to make the corresponding size determination a bit safer according to
the Linux coding style convention.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
drivers/video/fbdev/omap2/omapfb/vrfb.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/drivers/video/fbdev/omap2/omapfb/vrfb.c b/drivers/video/fbdev/omap2/omapfb/vrfb.c
index f346b02eee1d..54b51a7a290a 100644
--- a/drivers/video/fbdev/omap2/omapfb/vrfb.c
+++ b/drivers/video/fbdev/omap2/omapfb/vrfb.c
@@ -358,11 +358,7 @@ static int __init vrfb_probe(struct platform_device *pdev)
return PTR_ERR(vrfb_base);
num_ctxs = pdev->num_resources - 1;
-
- ctxs = devm_kzalloc(&pdev->dev,
- sizeof(struct vrfb_ctx) * num_ctxs,
- GFP_KERNEL);
-
+ ctxs = devm_kcalloc(&pdev->dev, num_ctxs, sizeof(*ctxs), GFP_KERNEL);
if (!ctxs)
return -ENOMEM;
--
2.12.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH] omapfb: Use devm_kcalloc() in vrfb_probe()
@ 2017-04-26 9:20 ` SF Markus Elfring
0 siblings, 0 replies; 8+ messages in thread
From: SF Markus Elfring @ 2017-04-26 9:20 UTC (permalink / raw)
To: linux-fbdev, linux-omap, Bartlomiej Zolnierkiewicz, Tomi Valkeinen
Cc: LKML, kernel-janitors
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Wed, 26 Apr 2017 11:08:30 +0200
* A multiplication for the size determination of a memory allocation
indicated that an array data structure should be processed.
Thus use the corresponding function "devm_kcalloc".
* Replace the specification of a data structure by a pointer dereference
to make the corresponding size determination a bit safer according to
the Linux coding style convention.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
drivers/video/fbdev/omap2/omapfb/vrfb.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/drivers/video/fbdev/omap2/omapfb/vrfb.c b/drivers/video/fbdev/omap2/omapfb/vrfb.c
index f346b02eee1d..54b51a7a290a 100644
--- a/drivers/video/fbdev/omap2/omapfb/vrfb.c
+++ b/drivers/video/fbdev/omap2/omapfb/vrfb.c
@@ -358,11 +358,7 @@ static int __init vrfb_probe(struct platform_device *pdev)
return PTR_ERR(vrfb_base);
num_ctxs = pdev->num_resources - 1;
-
- ctxs = devm_kzalloc(&pdev->dev,
- sizeof(struct vrfb_ctx) * num_ctxs,
- GFP_KERNEL);
-
+ ctxs = devm_kcalloc(&pdev->dev, num_ctxs, sizeof(*ctxs), GFP_KERNEL);
if (!ctxs)
return -ENOMEM;
--
2.12.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] omapfb: Use devm_kcalloc() in vrfb_probe()
2017-04-26 9:20 ` SF Markus Elfring
@ 2017-05-11 14:27 ` Bartlomiej Zolnierkiewicz
-1 siblings, 0 replies; 8+ messages in thread
From: Bartlomiej Zolnierkiewicz @ 2017-05-11 14:27 UTC (permalink / raw)
To: SF Markus Elfring
Cc: linux-fbdev, linux-omap, Tomi Valkeinen, LKML, kernel-janitors
Hi,
On Wednesday, April 26, 2017 11:20:07 AM SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Wed, 26 Apr 2017 11:08:30 +0200
>
> * A multiplication for the size determination of a memory allocation
> indicated that an array data structure should be processed.
> Thus use the corresponding function "devm_kcalloc".
>
> * Replace the specification of a data structure by a pointer dereference
> to make the corresponding size determination a bit safer according to
> the Linux coding style convention.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> drivers/video/fbdev/omap2/omapfb/vrfb.c | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/drivers/video/fbdev/omap2/omapfb/vrfb.c b/drivers/video/fbdev/omap2/omapfb/vrfb.c
> index f346b02eee1d..54b51a7a290a 100644
> --- a/drivers/video/fbdev/omap2/omapfb/vrfb.c
> +++ b/drivers/video/fbdev/omap2/omapfb/vrfb.c
> @@ -358,11 +358,7 @@ static int __init vrfb_probe(struct platform_device *pdev)
> return PTR_ERR(vrfb_base);
>
> num_ctxs = pdev->num_resources - 1;
> -
> - ctxs = devm_kzalloc(&pdev->dev,
> - sizeof(struct vrfb_ctx) * num_ctxs,
> - GFP_KERNEL);
> -
> + ctxs = devm_kcalloc(&pdev->dev, num_ctxs, sizeof(*ctxs), GFP_KERNEL);
This change makes the resulting binary larger by 24 bytes (probably
because of the need to have an additional function argument) and
I don't see an improvement from a security POV (pdev->num_resources
is based on the size of static tables from arch/arm/mach-omap2/fb.c).
I'm sorry but I'm not applying this patch.
> if (!ctxs)
> return -ENOMEM;
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] omapfb: Use devm_kcalloc() in vrfb_probe()
@ 2017-05-11 14:27 ` Bartlomiej Zolnierkiewicz
0 siblings, 0 replies; 8+ messages in thread
From: Bartlomiej Zolnierkiewicz @ 2017-05-11 14:27 UTC (permalink / raw)
To: SF Markus Elfring
Cc: linux-fbdev, linux-omap, Tomi Valkeinen, LKML, kernel-janitors
Hi,
On Wednesday, April 26, 2017 11:20:07 AM SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Wed, 26 Apr 2017 11:08:30 +0200
>
> * A multiplication for the size determination of a memory allocation
> indicated that an array data structure should be processed.
> Thus use the corresponding function "devm_kcalloc".
>
> * Replace the specification of a data structure by a pointer dereference
> to make the corresponding size determination a bit safer according to
> the Linux coding style convention.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> drivers/video/fbdev/omap2/omapfb/vrfb.c | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/drivers/video/fbdev/omap2/omapfb/vrfb.c b/drivers/video/fbdev/omap2/omapfb/vrfb.c
> index f346b02eee1d..54b51a7a290a 100644
> --- a/drivers/video/fbdev/omap2/omapfb/vrfb.c
> +++ b/drivers/video/fbdev/omap2/omapfb/vrfb.c
> @@ -358,11 +358,7 @@ static int __init vrfb_probe(struct platform_device *pdev)
> return PTR_ERR(vrfb_base);
>
> num_ctxs = pdev->num_resources - 1;
> -
> - ctxs = devm_kzalloc(&pdev->dev,
> - sizeof(struct vrfb_ctx) * num_ctxs,
> - GFP_KERNEL);
> -
> + ctxs = devm_kcalloc(&pdev->dev, num_ctxs, sizeof(*ctxs), GFP_KERNEL);
This change makes the resulting binary larger by 24 bytes (probably
because of the need to have an additional function argument) and
I don't see an improvement from a security POV (pdev->num_resources
is based on the size of static tables from arch/arm/mach-omap2/fb.c).
I'm sorry but I'm not applying this patch.
> if (!ctxs)
> return -ENOMEM;
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] omapfb: Use devm_kcalloc() in vrfb_probe()
2017-05-11 14:27 ` Bartlomiej Zolnierkiewicz
@ 2017-05-11 15:22 ` Bartlomiej Zolnierkiewicz
-1 siblings, 0 replies; 8+ messages in thread
From: Bartlomiej Zolnierkiewicz @ 2017-05-11 15:22 UTC (permalink / raw)
To: SF Markus Elfring
Cc: linux-fbdev, linux-omap, Tomi Valkeinen, LKML, kernel-janitors
On Thursday, May 11, 2017 04:27:19 PM Bartlomiej Zolnierkiewicz wrote:
> > @@ -358,11 +358,7 @@ static int __init vrfb_probe(struct platform_device *pdev)
> > return PTR_ERR(vrfb_base);
> >
> > num_ctxs = pdev->num_resources - 1;
> > -
> > - ctxs = devm_kzalloc(&pdev->dev,
> > - sizeof(struct vrfb_ctx) * num_ctxs,
> > - GFP_KERNEL);
> > -
> > + ctxs = devm_kcalloc(&pdev->dev, num_ctxs, sizeof(*ctxs), GFP_KERNEL);
>
> This change makes the resulting binary larger by 24 bytes (probably
> because of the need to have an additional function argument) and
24 bytes seemed too much for just an additional function argument
so I've checked the source:
static inline void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
{
return devm_kmalloc(dev, size, gfp | __GFP_ZERO);
}
static inline void *devm_kmalloc_array(struct device *dev,
size_t n, size_t size, gfp_t flags)
{
if (size != 0 && n > SIZE_MAX / size)
return NULL;
return devm_kmalloc(dev, n * size, flags);
}
static inline void *devm_kcalloc(struct device *dev,
size_t n, size_t size, gfp_t flags)
{
return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
}
The extra kcalloc() checks are inlined currently into each instance.
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] omapfb: Use devm_kcalloc() in vrfb_probe()
@ 2017-05-11 15:22 ` Bartlomiej Zolnierkiewicz
0 siblings, 0 replies; 8+ messages in thread
From: Bartlomiej Zolnierkiewicz @ 2017-05-11 15:22 UTC (permalink / raw)
To: SF Markus Elfring
Cc: linux-fbdev, linux-omap, Tomi Valkeinen, LKML, kernel-janitors
On Thursday, May 11, 2017 04:27:19 PM Bartlomiej Zolnierkiewicz wrote:
> > @@ -358,11 +358,7 @@ static int __init vrfb_probe(struct platform_device *pdev)
> > return PTR_ERR(vrfb_base);
> >
> > num_ctxs = pdev->num_resources - 1;
> > -
> > - ctxs = devm_kzalloc(&pdev->dev,
> > - sizeof(struct vrfb_ctx) * num_ctxs,
> > - GFP_KERNEL);
> > -
> > + ctxs = devm_kcalloc(&pdev->dev, num_ctxs, sizeof(*ctxs), GFP_KERNEL);
>
> This change makes the resulting binary larger by 24 bytes (probably
> because of the need to have an additional function argument) and
24 bytes seemed too much for just an additional function argument
so I've checked the source:
static inline void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
{
return devm_kmalloc(dev, size, gfp | __GFP_ZERO);
}
static inline void *devm_kmalloc_array(struct device *dev,
size_t n, size_t size, gfp_t flags)
{
if (size != 0 && n > SIZE_MAX / size)
return NULL;
return devm_kmalloc(dev, n * size, flags);
}
static inline void *devm_kcalloc(struct device *dev,
size_t n, size_t size, gfp_t flags)
{
return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
}
The extra kcalloc() checks are inlined currently into each instance.
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] omapfb: Use devm_kcalloc() in vrfb_probe()
2017-05-11 15:22 ` Bartlomiej Zolnierkiewicz
@ 2017-05-12 7:07 ` Geert Uytterhoeven
-1 siblings, 0 replies; 8+ messages in thread
From: Geert Uytterhoeven @ 2017-05-12 7:07 UTC (permalink / raw)
To: Bartlomiej Zolnierkiewicz
Cc: SF Markus Elfring, Linux Fbdev development list, linux-omap,
Tomi Valkeinen, LKML, kernel-janitors
On Thu, May 11, 2017 at 5:22 PM, Bartlomiej Zolnierkiewicz
<b.zolnierkie@samsung.com> wrote:
> On Thursday, May 11, 2017 04:27:19 PM Bartlomiej Zolnierkiewicz wrote:
>
>> > @@ -358,11 +358,7 @@ static int __init vrfb_probe(struct platform_device *pdev)
>> > return PTR_ERR(vrfb_base);
>> >
>> > num_ctxs = pdev->num_resources - 1;
>> > -
>> > - ctxs = devm_kzalloc(&pdev->dev,
>> > - sizeof(struct vrfb_ctx) * num_ctxs,
>> > - GFP_KERNEL);
>> > -
>> > + ctxs = devm_kcalloc(&pdev->dev, num_ctxs, sizeof(*ctxs), GFP_KERNEL);
>>
>> This change makes the resulting binary larger by 24 bytes (probably
>> because of the need to have an additional function argument) and
>
> 24 bytes seemed too much for just an additional function argument
> so I've checked the source:
>
> static inline void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
> {
> return devm_kmalloc(dev, size, gfp | __GFP_ZERO);
> }
> static inline void *devm_kmalloc_array(struct device *dev,
> size_t n, size_t size, gfp_t flags)
> {
> if (size != 0 && n > SIZE_MAX / size)
> return NULL;
> return devm_kmalloc(dev, n * size, flags);
> }
> static inline void *devm_kcalloc(struct device *dev,
> size_t n, size_t size, gfp_t flags)
> {
> return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
> }
>
> The extra kcalloc() checks are inlined currently into each instance.
And in this case the compiler cannot optimize them away as n is not
known at compile time.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] omapfb: Use devm_kcalloc() in vrfb_probe()
@ 2017-05-12 7:07 ` Geert Uytterhoeven
0 siblings, 0 replies; 8+ messages in thread
From: Geert Uytterhoeven @ 2017-05-12 7:07 UTC (permalink / raw)
To: Bartlomiej Zolnierkiewicz
Cc: SF Markus Elfring, Linux Fbdev development list, linux-omap,
Tomi Valkeinen, LKML, kernel-janitors
On Thu, May 11, 2017 at 5:22 PM, Bartlomiej Zolnierkiewicz
<b.zolnierkie@samsung.com> wrote:
> On Thursday, May 11, 2017 04:27:19 PM Bartlomiej Zolnierkiewicz wrote:
>
>> > @@ -358,11 +358,7 @@ static int __init vrfb_probe(struct platform_device *pdev)
>> > return PTR_ERR(vrfb_base);
>> >
>> > num_ctxs = pdev->num_resources - 1;
>> > -
>> > - ctxs = devm_kzalloc(&pdev->dev,
>> > - sizeof(struct vrfb_ctx) * num_ctxs,
>> > - GFP_KERNEL);
>> > -
>> > + ctxs = devm_kcalloc(&pdev->dev, num_ctxs, sizeof(*ctxs), GFP_KERNEL);
>>
>> This change makes the resulting binary larger by 24 bytes (probably
>> because of the need to have an additional function argument) and
>
> 24 bytes seemed too much for just an additional function argument
> so I've checked the source:
>
> static inline void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
> {
> return devm_kmalloc(dev, size, gfp | __GFP_ZERO);
> }
> static inline void *devm_kmalloc_array(struct device *dev,
> size_t n, size_t size, gfp_t flags)
> {
> if (size != 0 && n > SIZE_MAX / size)
> return NULL;
> return devm_kmalloc(dev, n * size, flags);
> }
> static inline void *devm_kcalloc(struct device *dev,
> size_t n, size_t size, gfp_t flags)
> {
> return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
> }
>
> The extra kcalloc() checks are inlined currently into each instance.
And in this case the compiler cannot optimize them away as n is not
known at compile time.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2017-05-12 7:07 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
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[not found] <CGME20170426092018epcas4p343e69e32255faa796e7c55c3e89e40f2@epcas4p3.samsung.com>
2017-04-26 9:20 ` [PATCH] omapfb: Use devm_kcalloc() in vrfb_probe() SF Markus Elfring
2017-04-26 9:20 ` SF Markus Elfring
2017-05-11 14:27 ` Bartlomiej Zolnierkiewicz
2017-05-11 14:27 ` Bartlomiej Zolnierkiewicz
2017-05-11 15:22 ` Bartlomiej Zolnierkiewicz
2017-05-11 15:22 ` Bartlomiej Zolnierkiewicz
2017-05-12 7:07 ` Geert Uytterhoeven
2017-05-12 7:07 ` Geert Uytterhoeven
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