UBSAN: object-size-mismatch in wg_xmit

[Corey Costello]

Get me off this fucking list ffs.



> On Jan 7, 2021, at 2:06 PM, Jeffrey Walton <noloader at gmail.com> wrote:
> 
> On Thu, Jan 7, 2021 at 2:03 PM Jason A. Donenfeld <Jason at zx2c4.com> wrote:
>> 
>> On Thu, Jan 7, 2021 at 1:22 PM Dmitry Vyukov <dvyukov at google.com> wrote:
>>> 
>>> On Mon, Dec 21, 2020 at 12:23 PM Jason A. Donenfeld <Jason at zx2c4.com> wrote:
>>>> 
>>>> ...
>>> 
>>> These UBSAN checks were just enabled recently.
>>> It's indeed super easy to trigger: 133083 VMs were crashed on this already:
>>> https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fsyzkaller.appspot.com%2fbug%3fextid%3d8f90d005ab2d22342b6d&c=E,1,RVpgZsRUCGs2jKlumiMAMnpeOF4QdiW5h8GDIsBJPz-orFNwvwCXnceC9n5Bhr1h-G2EsU0tlC7N4QUpHuF6tIMI7tTnBoRjAo5tT-Bk9-Fhe8CppuOL4mqdkA,,&typo=1
>>> So it's one of the top crashers by now.
>> 
>> Ahh, makes sense. So it is easily reproducible after all.
>> 
>> You're still of the opinion that it's a false positive, right? I
>> shouldn't spend more cycles on this?
> 
> You might consider making a test build with -fno-lto in case LTO is
> mucking things up.
> 
> Google Posts Patches So The Linux Kernel Can Be LTO-Optimized By
> Clang, https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fwww.phoronix.com%2fscan.php%3fpage%3dnews_item%26px%3dLinux-Kernel-Clang-LTO-Patches&c=E,1,7u3-jWadklYo8ai_XrPNvjnu46LLAyg0hqsGIaMPaoQ5UxtcNM84jrHUgSg4VciXKk9XVpwgyBwD85LbbW5_j195jSH6RrAej45I1kr_XfQ,&typo=1
> 
> Jeff