Re: [PATCH] fbdev: fix possible NULL pointer derefernce

[DaeSeok Youn]

Hello,

2014-04-16 21:38 GMT+09:00 Jean-Christophe PLAGNIOL-VILLARD
<plagnioj@xxxxxxxxxxxx>:
>
> On Apr 16, 2014, at 5:40 PM, Daeseok Youn <daeseok.youn@xxxxxxxxx> wrote:
>
>>
>> The spec->modedb can be NULL by fb_create_modedb().
>>
>> And also smatch says:
>> drivers/video/fbdev/core/fbmon.c:975 fb_edid_to_monspecs() error:
>> potential null dereference 'specs->modedb'.
>> (fb_create_modedb returns null)
>>
>> Signed-off-by: Daeseok Youn <daeseok.youn@xxxxxxxxx>
>> ---
>> drivers/video/fbdev/core/fbmon.c |    3 +++
>> 1 files changed, 3 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/video/fbdev/core/fbmon.c b/drivers/video/fbdev/core/fbmon.c
>> index c204ebe..db274ca 100644
>> --- a/drivers/video/fbdev/core/fbmon.c
>> +++ b/drivers/video/fbdev/core/fbmon.c
>> @@ -966,6 +966,9 @@ void fb_edid_to_monspecs(unsigned char *edid, struct fb_monspecs *specs)
>>
>>       specs->modedb = fb_create_modedb(edid, &specs->modedb_len);
>>
>> +     if (!specs->modedb)
>> +             return;
>> +
>
> we need to return an error and trace it
Yes, you're right. I will change return type from void to int and add
to handle an error when this function(fb_edid_to_monspecs) is called.

I will send this patch as your comment.

Thanks for review.

Daeseok Youn.
>
> Best Regards,
> J.
>>       /*
>>        * Workaround for buggy EDIDs that sets that the first
>>        * detailed timing is preferred but has not detailed
>> --
>> 1.7.4.4
>>
>
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