The header-block PT_LOAD has the highest address but was the first
loadable entry in the table. Linux before 5.18 sizes the ET_DYN mapping
from the first and last PT_LOAD entries in table order, so the output
failed to exec with SIGSEGV. Write PT_PHDR and PT_INTERP first, sort the
kept PT_LOAD entries by address, and place the extra and header blocks
after them.
The segment filter dropped every header in the PT_LOOS..PT_HIOS range,
which includes PT_GNU_EH_FRAME. The unwinders find the executable's
unwind tables through that header, so no C++ exception thrown in the
main executable could be caught on Linux.
The header is kept only when the output program header table still fits
in the input's table; otherwise it is dropped as before, with a warning.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HeC9bA3n74TzJRYv9AgBE8
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