[dvipdfmx] Intermittent xdvipdfmx failure

[Shunsaku Hirata]

Hi,

Thank you for the report.

I tried to reproduce the problem but was unable to do so.

As I don't own the same installation as you, I had used my
own build of dvipdfmx 20201111 on MinGW/Win10.
The provided example was processed hundreds of times
but I had no chance to observe the same error.

I also tried the valgrind program to verify memory related
errors on Ubuntu on VirtualBox, but no access violation
error was detected.


Thanks,
Shunsaku Hirata

2021年1月24日(日) 6:46 Tim Eyre <mail at nihilist.org.uk>:
>
> I recently upgraded to TeXLive 2020 on Windows 10. I recently noticed that documents that compiled OK under TeXLive 2013 were intermittently failing under TeXLive 2020. In the failure cases, XeTeX only partially generated the PDF file.
>
> Investigation revealed that xdvipdfmx was intermittently failing when presented with heavy use of the Batang Korean font, which is a built-in Windows 10 font. Here is a minimal example:
>
> \font\Korean="Batang" at 10pt
> \newcount\CrashCount
> \CrashCount=1
> \loop\ifnum\CrashCount<4000
>     X {\Korean 서울} X
>   \advance\CrashCount by1
>   \repeat
> \bye
>
> It is usually necessary to process a file like this several times to trigger the failure. Therefore I wrote a batch job to help with diagnosis:
>
> @echo off
> xetex -no-pdf test.tex
> :LOOPSTART
> xdvipdfmx test.xdv
> if "%ERRORLEVEL%"=="0" goto LOOPSTART
> echo Failed with error %ERRORLEVEL%
>
> The XeTeX log file gives the following error, indicating that xdvipdfmx crashed on an Access Violation:
>
> Error -1073741819 (driver return code) generating output
>
> In Windows,  -1073741819 = 0xC0000005 =  Access Violation
>
> The version of xdvipdfmx I am using is 20201111.
>
> I have worked around the issue by putting a retry loop around my call out to xetex in my Python code. Therefore this glitch is not causing me a problem. However, I feel a duty to report it to the (x)dvipdfmx community so that someone can fix it if they feel that doing so is the right thing to do.
>
> Tim