[Rd] R 4.0.2 64-bit Windows hangs

[Tomas Kalibera]

On 8/22/20 8:26 PM, Tomas Kalibera wrote:
> On 8/22/20 7:58 PM, Jeroen Ooms wrote:
>> On Sat, Aug 22, 2020 at 8:39 AM Tomas Kalibera 
>> <tomas.kalibera using gmail.com> wrote:
>>> On 8/21/20 11:45 PM, m19tdn+9alxwj7d2bmk--- via R-devel wrote:
>>>> Ah yes, this is related. I reported v2010 below, but it looks like 
>>>> I was updated to this Insider Build overnight without my knowledge, 
>>>> and conflated it with the new installation R v4 this morning.
>>>>
>>>> I will continue to look into the issue with the methods Tomas 
>>>> mentioned.
>>> It is interesting that a rare 5 years old problem would re-appear on
>>> current Insider builds. Which build of Windows are you running exactly?
>>> I've seen another report about a crash on 20190.1000. It'd be nice to
>>> know if it is present also in newer builds, i.e. in 20197.
>> I installed the latest 20197 build in a vm, and I can indeed reproduce
>> this problem.
>>
>> What seems to be happening is that R triggers an infinite recursion in
>> Windows unwinding mechanism, and eventually dies with a stack
>> overflow. Attached a backtrace of the initial 100 frames of the main
>> thread (the pattern in the top ~30 frames continues forever).
>>
>> The microsoft blog doesn't mention anything related to exception
>> handling has changed in recent versions:
>> https://docs.microsoft.com/en-us/windows-insider/at-home/active-dev-branch 
>>
>
> Thanks, unfortunately that does not ring any bells (except below), I 
> can't guess from this what is the underlying cause of the problem. 
> There may be something wrong in how we use setjmp/longjmp or how 
> setjmp/longjmp works on Windows.
>
> It reminds me of a problem I've been debugging few days ago, when 
> longjump implementation segfaults on Windows 10 (recent but not 
> Insider build) probably soon after unwinding the stack, but only with 
> GCC 10 / MinGW 7 and only in one of the no-segfault tests, and only 
> with -03 (not -O2, not with with -O3 -fno-split-loops). The problem 
> was sensitive to these optimization options interestingly on the call 
> site of long jump (do_abs), even when it was not an immediate caller 
> of the longjump. I've not tracked this down yet, it will require 
> looking at the assembly level, and I was suspecting a compiler error 
> causing the compiler to generate code that messes with the stack or 
> registers in a way that impacts the upcoming jump. But now as we have 
> this other problem with setjmp/logjmp, the compiler may not be the top 
> suspect anymore.
>
> I may not be able to work on this in the next few days or a week, so 
> if anyone gets there first, please let me know what you find out.

Btw could you please try out if the UCRT build of R crashes as well in 
the Insider Windows build ?

https://www.r-project.org/nosvn/winutf8/R-devel-win.exe

Thanks
Tomas

(from 
https://developer.r-project.org/Blog/public/2020/07/30/windows/utf-8-build-of-r-and-cran-packages)

>
> Thanks,
> Tomas
>
>