lkml.org 
[lkml]   [2017]   [Jul]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] [v2] kasan: avoid -Wmaybe-uninitialized warning
On Tue, Jul 25, 2017 at 2:06 PM, Andrey Ryabinin
<aryabinin@virtuozzo.com> wrote:
> On 07/25/2017 10:17 AM, Arnd Bergmann wrote:
>> On Mon, Jul 24, 2017 at 1:35 PM, Alexander Potapenko <glider@google.com> wrote:
>>> On Fri, Jul 21, 2017 at 11:02 PM, Arnd Bergmann <arnd@arndb.de> wrote:
>>
>>>> diff --git a/mm/kasan/report.c b/mm/kasan/report.c
>>>> index 04bb1d3eb9ec..28fb222ab149 100644
>>>> --- a/mm/kasan/report.c
>>>> +++ b/mm/kasan/report.c
>>>> @@ -111,6 +111,9 @@ static const char *get_wild_bug_type(struct kasan_access_info *info)
>>>> {
>>>> const char *bug_type = "unknown-crash";
>>>>
>>>> + /* shut up spurious -Wmaybe-uninitialized warning */
>>>> + info->first_bad_addr = (void *)(-1ul);
>>>> +
>>> Why don't we initialize info.first_bad_addr in kasan_report(), where
>>> info is allocated?
>>
>> I'm just trying to shut up a particular warning here where gcc can't figure out
>> by itself that it is initialized. Setting an invalid address at
>> allocation time would
>> prevent gcc from warning even for any trivial bug where we use the incorrect
>> value in the normal code path, in case someone later wants to modify the
>> code further and makes a mistake.
>>
>
> 'info->first_bad_addr' could be initialized to the correct value. That would be 'addr' itself
> for 'wild' type of bugs.
> Initialization in get_wild_bug_type() looks a bit odd and off-place.

Yes, that makes sense. I'll send a new version then.

Arnd

\
 
 \ /
  Last update: 2017-07-25 16:53    [W:0.052 / U:0.884 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site