lkml.org 
[lkml]   [2013]   [Feb]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v2] i2c: busses/i2c-pxa.c: fix potential null pointer dereference error
From
On Tue, Feb 5, 2013 at 6:25 PM, Cong Ding <dinggnu@gmail.com> wrote:
> On Tue, Feb 05, 2013 at 09:14:08AM +0800, Haojian Zhuang wrote:
>> On Tue, Feb 5, 2013 at 8:05 AM, Cong Ding <dinggnu@gmail.com> wrote:
>> > If it goes to eclk through line 1107, the variable res would be NULL. It will
>> > cause a null pointer dereference error if we call release_mem_region.
>> >
>> > Signed-off-by: Cong Ding <dinggnu@gmail.com>
>> > ---
>> > drivers/i2c/busses/i2c-pxa.c | 3 ++-
>> > 1 file changed, 2 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
>> > index 1034d93..00df535 100644
>> > --- a/drivers/i2c/busses/i2c-pxa.c
>> > +++ b/drivers/i2c/busses/i2c-pxa.c
>> > @@ -1211,7 +1211,8 @@ 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;
>> > }
>> >
>> >
>>
>> No. I don't agree on this. Your fix can't resolve all potential issues.
>>
>> i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
devm_kzalloc
>> if (!i2c) {
>> ret = -ENOMEM;
>> goto emalloc;
return -ENOMEM;
>> }
>>
>> ret = i2c_pxa_probe_dt(dev, i2c, &i2c_type);
>> if (ret > 0)
>> ret = i2c_pxa_probe_pdata(dev, i2c, &i2c_type);
>> if (ret < 0)
>> goto eclk;
return ret;
>>
>> res = platform_get_resource(dev, IORESOURCE_MEM, 0);
>> irq = platform_get_irq(dev, 0);
>> if (res == NULL || irq < 0) {
>> ret = -ENODEV;
>> goto eclk;
ditto
>> }
>>
>> if (!request_mem_region(res->start, resource_size(res), res->name)) {
>> ret = -ENOMEM;
>> goto eclk;
ditto
>> }
>>
>> We shouldn't jump to eclk for these error cases. Then we needn't to add
>> checking on res.
> So what do you suggest to do for these error cases?
> - cong
>


\
 
 \ /
  Last update: 2013-02-05 13:01    [W:0.075 / U:0.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site