mmap_32bit_base not initialised from -xm unless initLinker is called

In a mixed Haskell/other code program the default setting for mmap_32bit_base (0x40000000) might already be allocated once the RTS goes to allocate it (probably for the dynamic wrapper FFI functionality?), the RTS then fails with a message suggesting to set the base with -xm.

Setting -xm doesn't work because mmap_32bit_base is not initialised with -xm in a normal program, it is only initialised in initLinker.

The calls seem to roughly be:

createAdjustor
alloc_adjustor
alloc_adjustor_chunk
allocateExecPage
mmapAnonForLinker
mmapForLinker

Expected behavior

Always initialise mmap_32bit_base with value from -xm or don't use the mmapForLinker functionality at all for the adjustors (do they need this 32 bit address size thing?).

Environment

• GHC version used: 9.6-9.10
• Operating System: Linux
• System Architecture: x86-64