* [PATCH] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference
@ 2014-05-17 17:14 Rickard Strandqvist
2014-05-17 17:18 ` Mateusz Guzik
2014-06-01 20:26 ` Wolfram Sang
0 siblings, 2 replies; 4+ messages in thread
From: Rickard Strandqvist @ 2014-05-17 17:14 UTC (permalink / raw)
To: Wolfram Sang, Grant Likely
Cc: Rickard Strandqvist, Rob Herring, Jingoo Han, Leilei Shang,
Daniel Drake, linux-i2c, linux-kernel, devicetree
There is otherwise a risk of a possible null pointer dereference.
Was largely found by using a static code analysis program called cppcheck.
Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
---
drivers/i2c/busses/i2c-pxa.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index bbe6dfb..dbe5ebe 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -1269,7 +1269,9 @@ eremap:
eclk:
kfree(i2c);
emalloc:
- release_mem_region(res->start, resource_size(res));
+ if(res) {
+ release_mem_region(res->start, resource_size(res));
+ }
return ret;
}
--
1.7.10.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference
2014-05-17 17:14 [PATCH] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference Rickard Strandqvist
@ 2014-05-17 17:18 ` Mateusz Guzik
2014-06-01 20:26 ` Wolfram Sang
1 sibling, 0 replies; 4+ messages in thread
From: Mateusz Guzik @ 2014-05-17 17:18 UTC (permalink / raw)
To: Rickard Strandqvist
Cc: Wolfram Sang, Grant Likely, Rob Herring, Jingoo Han, Leilei Shang,
Daniel Drake, linux-i2c, linux-kernel, devicetree
On Sat, May 17, 2014 at 07:14:08PM +0200, Rickard Strandqvist wrote:
> There is otherwise a risk of a possible null pointer dereference.
>
> Was largely found by using a static code analysis program called cppcheck.
>
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
> ---
> drivers/i2c/busses/i2c-pxa.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> index bbe6dfb..dbe5ebe 100644
> --- a/drivers/i2c/busses/i2c-pxa.c
> +++ b/drivers/i2c/busses/i2c-pxa.c
> @@ -1269,7 +1269,9 @@ eremap:
> eclk:
> kfree(i2c);
> emalloc:
> - release_mem_region(res->start, resource_size(res));
> + if(res) {
> + release_mem_region(res->start, resource_size(res));
> + }
> return ret;
> }
>
This looks incorrect.
request_mem_region, which I believe is a prerequisite for this function
may not be called when you jump here.
--
Mateusz Guzik
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference
2014-05-17 17:14 [PATCH] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference Rickard Strandqvist
2014-05-17 17:18 ` Mateusz Guzik
@ 2014-06-01 20:26 ` Wolfram Sang
2014-06-02 1:55 ` Jingoo Han
1 sibling, 1 reply; 4+ messages in thread
From: Wolfram Sang @ 2014-06-01 20:26 UTC (permalink / raw)
To: Rickard Strandqvist
Cc: Grant Likely, Rob Herring, Jingoo Han, Leilei Shang, Daniel Drake,
linux-i2c, linux-kernel, devicetree
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On Sat, May 17, 2014 at 07:14:08PM +0200, Rickard Strandqvist wrote:
> There is otherwise a risk of a possible null pointer dereference.
>
> Was largely found by using a static code analysis program called cppcheck.
It is useful to put the output of the analyzer here.
>
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
> ---
> drivers/i2c/busses/i2c-pxa.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> index bbe6dfb..dbe5ebe 100644
> --- a/drivers/i2c/busses/i2c-pxa.c
> +++ b/drivers/i2c/busses/i2c-pxa.c
> @@ -1269,7 +1269,9 @@ eremap:
> eclk:
> kfree(i2c);
> emalloc:
> - release_mem_region(res->start, resource_size(res));
> + if(res) {
> + release_mem_region(res->start, resource_size(res));
> + }
The proper fix is to move the release to the proper place, before kfree.
Even better would probably be a devm_* conversion.
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference
2014-06-01 20:26 ` Wolfram Sang
@ 2014-06-02 1:55 ` Jingoo Han
0 siblings, 0 replies; 4+ messages in thread
From: Jingoo Han @ 2014-06-02 1:55 UTC (permalink / raw)
To: 'Rickard Strandqvist', 'Wolfram Sang'
Cc: 'Grant Likely', 'Rob Herring',
'Leilei Shang', 'Daniel Drake', linux-i2c,
linux-kernel, devicetree, 'Jingoo Han'
On Monday, June 02, 2014 5:27 AM, Wolfram Sang wrote:
> On Sat, May 17, 2014 at 07:14:08PM +0200, Rickard Strandqvist wrote:
> > There is otherwise a risk of a possible null pointer dereference.
> >
> > Was largely found by using a static code analysis program called cppcheck.
>
> It is useful to put the output of the analyzer here.
>
> >
> > Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
> > ---
> > drivers/i2c/busses/i2c-pxa.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> > index bbe6dfb..dbe5ebe 100644
> > --- a/drivers/i2c/busses/i2c-pxa.c
> > +++ b/drivers/i2c/busses/i2c-pxa.c
> > @@ -1269,7 +1269,9 @@ eremap:
> > eclk:
> > kfree(i2c);
> > emalloc:
> > - release_mem_region(res->start, resource_size(res));
> > + if(res) {
> > + release_mem_region(res->start, resource_size(res));
> > + }
>
> The proper fix is to move the release to the proper place, before kfree.
> Even better would probably be a devm_* conversion.
+1
I agree with Wolfram Sang's opinion. Please call release_mem_region()
prior to kfree().
One more thing, don't use braces when a single statement
is used. Please refer to 'Chapter 3: Placing Braces and Spaces'
of 'Documentation/CodingStyle'.
Best regards,
Jingoo Han
^ permalink raw reply [flat|nested] 4+ messages in thread
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2014-05-17 17:14 [PATCH] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference Rickard Strandqvist
2014-05-17 17:18 ` Mateusz Guzik
2014-06-01 20:26 ` Wolfram Sang
2014-06-02 1:55 ` Jingoo Han
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