* [PATCH] video: fbdev: skeletonfb.c: Adding code to managing allocation error
@ 2014-06-21 13:17 Rickard Strandqvist
2014-06-21 13:58 ` Joe Perches
0 siblings, 1 reply; 4+ messages in thread
From: Rickard Strandqvist @ 2014-06-21 13:17 UTC (permalink / raw)
To: Jean-Christophe Plagniol-Villard, Tomi Valkeinen
Cc: Rickard Strandqvist, Jingoo Han, Daniel Vetter, Joe Perches,
linux-fbdev, linux-kernel
Adding missing code for managing a memory allocation error that may occur.
This was partly found using a static code analysis program called cppcheck.
Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
---
drivers/video/fbdev/skeletonfb.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/video/fbdev/skeletonfb.c b/drivers/video/fbdev/skeletonfb.c
index fefde7c..ee6dc7e 100644
--- a/drivers/video/fbdev/skeletonfb.c
+++ b/drivers/video/fbdev/skeletonfb.c
@@ -692,6 +692,7 @@ static int xxxfb_probe(struct pci_dev *dev, const struct pci_device_id *ent)
if (!info) {
/* goto error path */
+ return -ENOMEM;
}
par = info->par;
@@ -746,6 +747,7 @@ static int xxxfb_probe(struct pci_dev *dev, const struct pci_device_id *ent)
info->pixmap.addr = kmalloc(PIXMAP_SIZE, GFP_KERNEL);
if (!info->pixmap.addr) {
/* goto error */
+ return -ENOMEM;
}
info->pixmap.size = PIXMAP_SIZE;
--
1.7.10.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] video: fbdev: skeletonfb.c: Adding code to managing allocation error
2014-06-21 13:17 [PATCH] video: fbdev: skeletonfb.c: Adding code to managing allocation error Rickard Strandqvist
@ 2014-06-21 13:58 ` Joe Perches
2014-06-21 20:48 ` Geert Uytterhoeven
0 siblings, 1 reply; 4+ messages in thread
From: Joe Perches @ 2014-06-21 13:58 UTC (permalink / raw)
To: Rickard Strandqvist, Geert Uytterhoeven
Cc: Jean-Christophe Plagniol-Villard, Tomi Valkeinen, Jingoo Han,
Daniel Vetter, linux-fbdev, linux-kernel
(Adding Geert, who probably wrote most of this
and likely might have forgotten all of it)
On Sat, 2014-06-21 at 15:17 +0200, Rickard Strandqvist wrote:
> Adding missing code for managing a memory allocation error that may occur.
>
> This was partly found using a static code analysis program called cppcheck.
skeletonfb.c is not meant to be compiled.
It's a sample driver template.
Those /* goto error path */ lines are for
driver writers that use this to figure out
what to do.
The second return is not correct as it would
not free the first alloc'd block.
> diff --git a/drivers/video/fbdev/skeletonfb.c b/drivers/video/fbdev/skeletonfb.c
[]
> @@ -692,6 +692,7 @@ static int xxxfb_probe(struct pci_dev *dev, const struct pci_device_id *ent)
>
> if (!info) {
> /* goto error path */
> + return -ENOMEM;
> }
>
> par = info->par;
> @@ -746,6 +747,7 @@ static int xxxfb_probe(struct pci_dev *dev, const struct pci_device_id *ent)
> info->pixmap.addr = kmalloc(PIXMAP_SIZE, GFP_KERNEL);
> if (!info->pixmap.addr) {
> /* goto error */
> + return -ENOMEM;
> }
>
> info->pixmap.size = PIXMAP_SIZE;
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] video: fbdev: skeletonfb.c: Adding code to managing allocation error
2014-06-21 13:58 ` Joe Perches
@ 2014-06-21 20:48 ` Geert Uytterhoeven
2014-06-21 21:32 ` Rickard Strandqvist
0 siblings, 1 reply; 4+ messages in thread
From: Geert Uytterhoeven @ 2014-06-21 20:48 UTC (permalink / raw)
To: Joe Perches
Cc: Rickard Strandqvist, Jean-Christophe Plagniol-Villard,
Tomi Valkeinen, Jingoo Han, Daniel Vetter,
Linux Fbdev development list, linux-kernel
On Sat, Jun 21, 2014 at 3:58 PM, Joe Perches <joe@perches.com> wrote:
> (Adding Geert, who probably wrote most of this
> and likely might have forgotten all of it)
>
> On Sat, 2014-06-21 at 15:17 +0200, Rickard Strandqvist wrote:
>> Adding missing code for managing a memory allocation error that may occur.
>>
>> This was partly found using a static code analysis program called cppcheck.
>
> skeletonfb.c is not meant to be compiled.
> It's a sample driver template.
Yep.
> Those /* goto error path */ lines are for
> driver writers that use this to figure out
> what to do.
Still, it's nice if a sample driver has correct error handling.
Just comments are not good enough as guidance for some people ;-)
> The second return is not correct as it would
> not free the first alloc'd block.
Indeed. Better do it right.
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] 4+ messages in thread
* Re: [PATCH] video: fbdev: skeletonfb.c: Adding code to managing allocation error
2014-06-21 20:48 ` Geert Uytterhoeven
@ 2014-06-21 21:32 ` Rickard Strandqvist
0 siblings, 0 replies; 4+ messages in thread
From: Rickard Strandqvist @ 2014-06-21 21:32 UTC (permalink / raw)
To: Geert Uytterhoeven
Cc: Joe Perches, Jean-Christophe Plagniol-Villard, Tomi Valkeinen,
Jingoo Han, Daniel Vetter, Linux Fbdev development list,
linux-kernel
Hi
Sounds like a good idea to have better error handling although it is
an example, even more important there.
At the first return nothing has been allocated, so it's ok I guess.
At the second I reflect about adding some deallocation, there are
comments on some form of goto error part which would appropriately
handle a deallocation. But all the other places in the code is just do
a return, that was why I chose to do it at the second return to.
Kind regards
Rickard Strandqvist
2014-06-21 22:48 GMT+02:00 Geert Uytterhoeven <geert@linux-m68k.org>:
> On Sat, Jun 21, 2014 at 3:58 PM, Joe Perches <joe@perches.com> wrote:
>> (Adding Geert, who probably wrote most of this
>> and likely might have forgotten all of it)
>>
>> On Sat, 2014-06-21 at 15:17 +0200, Rickard Strandqvist wrote:
>>> Adding missing code for managing a memory allocation error that may occur.
>>>
>>> This was partly found using a static code analysis program called cppcheck.
>>
>> skeletonfb.c is not meant to be compiled.
>> It's a sample driver template.
>
> Yep.
>
>> Those /* goto error path */ lines are for
>> driver writers that use this to figure out
>> what to do.
>
> Still, it's nice if a sample driver has correct error handling.
> Just comments are not good enough as guidance for some people ;-)
>
>> The second return is not correct as it would
>> not free the first alloc'd block.
>
> Indeed. Better do it right.
>
> 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] 4+ messages in thread
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2014-06-21 13:17 [PATCH] video: fbdev: skeletonfb.c: Adding code to managing allocation error Rickard Strandqvist
2014-06-21 13:58 ` Joe Perches
2014-06-21 20:48 ` Geert Uytterhoeven
2014-06-21 21:32 ` Rickard Strandqvist
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