On Wed, Aug 26, 2020 at 7:54 PM Tomas Kalibera <tomas.kalib...@gmail.com> wrote: > > On 8/25/20 6:14 PM, Tomas Kalibera wrote: > > On 8/22/20 9:33 PM, Jeroen Ooms wrote: > >> On Sat, Aug 22, 2020 at 9:10 PM Tomas Kalibera > >> <tomas.kalib...@gmail.com> wrote: > >>> 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.kalib...@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 ? > >> Yes, it hangs in exactly the same way, except that the backtrace shows > >> > >> ucrtbase!.intrinsic_setjmpex () from C:\WINDOWS\System32\ucrtbase.dll > >> > >> Instead of msvcrt!_setjmpex (as expected of course). > > > > Thanks. I found what is causing the problem I observed with > > GCC10/stock Windows 10, I expect this is the same one as in the > > Insider build. > > I will investigate further, > > > > Tomas > > > It seems the problem is between MinGW-W64 and Windows, and really it > causes both the reported crashes in an Insider build (I tested in 20197) > and in my GCC 10 builds in a single "no-segfault" test. setjmp is > implemented using Windows call _setjmpex, which has a second argument > argument, which is set differently by MinGW based on GCC version. When I > set this argument as MinGW-W64 did on early versions of GCC, > mingw_getsp(), it fixes/hides the problems on my systems. Perl5 uses a > similar workaround, but otherwise there is no solid base (documentation, > specification, etc) I am aware of for this change, so this may take some > more time to be properly fixed. Still, if anyone experiments with this > workaround and finds a problem, please let me know. In particular, I am > curious whether it works on earlier versions of Windows (at least with > check-all, including recommended packages).
FYI, the problem has disappeared on Windows dev built 20201 (released yesterday), so it may have been a Windows bug. That is not to say there is no bug on the R/mingw side, but at least the current and past releases of R are working again on the latest versions of Windows, which is a big relief. ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel