On 6/20/20 1:27 PM, Sam Ravnborg wrote:
> Hi Gustavo.
>
> On Wed, Jun 17, 2020 at 12:56:47PM -0500, Gustavo A. R. Silva wrote:
>> Make use of the struct_size() helper instead of an open-coded version
>> in order to avoid any potential type mistakes.
>>
>> This code was detected with the help of Coccinelle and, audited and
>> fixed manually.
>>
>> Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
>
> struct_size is defined in overflow.h - which is not included by fs.h.
> So we rely on overflow.h being pulled in by some other header - maybe
> slab.h in this case.
> Seems fragile, should this patch add an include of overflow.h?
$ git grep struct_size drivers/|wc -l
697
$ git grep overflow\\.h drivers/|wc -l
8
$ git grep overflow\\.h include/linux/
include/linux/device.h:#include <linux/overflow.h>
include/linux/mm.h:#include <linux/overflow.h>
include/linux/slab.h:#include <linux/overflow.h>
include/linux/vmalloc.h:#include <linux/overflow.h>
so I've applied the patch as it is (hoping that the issue is so
widespread that no-one tries to remove overflow.h from slab.h
without fixing drivers at the same time)..
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
> Sam
>
>> ---
>> include/linux/fb.h | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/linux/fb.h b/include/linux/fb.h
>> index 3b4b2f0c6994..2b530e6d86e4 100644
>> --- a/include/linux/fb.h
>> +++ b/include/linux/fb.h
>> @@ -506,8 +506,9 @@ struct fb_info {
>> };
>>
>> static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {
>> - struct apertures_struct *a = kzalloc(sizeof(struct apertures_struct)
>> - + max_num * sizeof(struct aperture), GFP_KERNEL);
>> + struct apertures_struct *a;
>> +
>> + a = kzalloc(struct_size(a, ranges, max_num), GFP_KERNEL);
>> if (!a)
>> return NULL;
>> a->count = max_num;
>> --
>> 2.27.0
>>
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