graph (plotutils) seg-faulting

[Jon Turney]

On 19/07/2020 16:55, briand@pounceofcats.com wrote:
> oh good grief.  i just tried this on my home win 10 box, and works perfectly.
> 
> unfortunately, my work box, which has a history of weird problems with cygwin, is the one having the problem.  there's too much work-related stuff in the cygcheck output for me to pass it on.
> 
> However the strace is ok, so i have attached it.
> 
> Just to be clear,
> 
>    graph --help
> 
> segfaults, so the problem is at a _really_ low level.

> --- Process 3080 created
> --- Process 3080 loaded C:\Windows\System32\ntdll.dll at 00007ffc95740000
> --- Process 3080 loaded C:\Windows\System32\kernel32.dll at 00007ffc93db0000
> --- Process 3080 loaded C:\Windows\System32\KernelBase.dll at 00007ffc92860000
[...]
> --- Process 3080 loaded C:\cygwin64\bin\cygplot-2.dll at 0000000000600000
> --- Process 3080 unloaded DLL at 0000000000600000
> --- Process 3080 loaded C:\cygwin64\bin\cygwin1.dll at 0000000000ce0000
> --- Process 3080 unloaded DLL at 0000000000ce0000
> --- Process 3080 loaded C:\cygwin64\bin\cygplot-2.dll at 0000000000600000
> --- Process 3080 loaded C:\cygwin64\bin\cygwin1.dll at 0000000000ee0000
> --- Process 3080 thread 9632 created
> --- Process 3080 unloaded DLL at 0000000000ee0000
> --- Process 3080 loaded C:\cygwin64\bin\cygpng16-16.dll at 0000000000190000
> --- Process 3080 unloaded DLL at 0000000000190000
> --- Process 3080 loaded C:\cygwin64\bin\cygXaw-7.dll at 0000000000730000
> --- Process 3080 loaded C:\cygwin64\bin\cygX11-6.dll at 0000000000ee0000
> --- Process 3080 unloaded DLL at 0000000000730000
> --- Process 3080 unloaded DLL at 0000000000ee0000
> --- Process 3080 loaded C:\cygwin64\bin\cygwin1.dll at 00000000014f0000

That's really very odd.

I guess this is the fork code desperately trying to force the DLL memory 
layout to match in the child, but should that even happen if it's being 
run from strace?  It's also strange that it tries to reposition cygwin1.dll.