Re: [PATCH 2/3] asm-generic, x86: wrap atomic operations

Arnd Bergmann
2017-03-22T12:49:12Z

On Wed, Mar 22, 2017 at 1:14 PM, Dmitry Vyukov <dvyukov@google.com> wrote:
> On Wed, Mar 22, 2017 at 12:30 PM, Arnd Bergmann <arnd@arndb.de> wrote:
>> On Wed, Mar 22, 2017 at 11:42 AM, Dmitry Vyukov <dvyukov@google.com> wrote:
>>> On Tue, Mar 21, 2017 at 10:20 PM, Arnd Bergmann <arnd@arndb.de> wrote:
>>>> On Tue, Mar 21, 2017 at 7:06 PM, Dmitry Vyukov <dvyukov@google.com> wrote:
>>>
>>> Initially I've tested with my stock gcc 4.8.4 (Ubuntu
>>> 4.8.4-2ubuntu1~14.04.3) and amusingly it works. But I can reproduce
>>> the bug with 7.0.1.
>>
>> It's probably because gcc-4.8 didn't support KASAN yet, so the added
>> check had no effect.
>
> I've tested without KASAN with both compilers.

Ah ok. I had not realized that this happened even without KASAN. I only saw this
problem in one out of hundreds of defconfig builds and assumed it was related
since this came from a kasan change.

Arnd