fork error when trying to call VirtualAlloc with size==0

Thu May 22 17:17:16 GMT 2025

On 2025年5月21日, Jeremy Drake via Cygwin wrote:
> On 2025年5月21日, Jeremy Drake via Cygwin wrote:
>> > the child to not be very fruitful, but maybe there's some debugging to be
> > done there
>> Well, found the bug that results in a 0 size. size is a DWORD, but
> mb.RegionSize is 0x200000000. mb.RegionSize is SIZE_T, but I figure
> size_t is appropriate.

I've sent a patch
https://cygwin.com/pipermail/cygwin-patches/2025q2/013726.html for review.
Now I get the correct error message:
 0 [main] rustc 1569 child_info_fork::abort: unable to remap
\??\V:\rust\rustc-nightly-src\build-MSYS\x86_64-pc-cygwin\stage0-rustc\release\deps\tracing_attributes-0e8ab81319ad49f1.dll
(using V:\rust\rustc-nightly-src\build-MSYS\x86_64-pc-cygwin\stage0-rustc\release\deps\tracing_attributes-0e8ab81319ad49f1.dll)
to same address as parent (0x2090000) - try running rebaseall
Ultimately, playing whack-a-mole in a 64-bit address space hoping that the
DLL will load in the same place as the parent is an exercise in futility,
especially in only 6 attempts.