GC_move_long_link failed on Linux/x86_64 if redirect malloc and gc-debug

[ivmai]

Source: release-7_4 (d50367e)
Build: https://app.travis-ci.com/github/ivmai/bdwgc/jobs/625906318
Host: Ubuntu 16.04.7 LTS / x86_64
Compiler: gcc
How to build/test: ./configure --enable-redirect-malloc --enable-gc-debug --enable-cplusplus --enable-gc-assertions && make -j check
Occurrence: 1/3
Output (gctest.log):

GC Warning: USE_PROC_FOR_LIBRARIES + GC_LINUX_THREADS performs poorly.
GC_move_long_link(link,link) failed
Test failed

Probably relates to issue #288

[ivmai]

Alternative output:

GC_move_disappearing_link(link,link) failed

[ivmai]

Observed also on release-8_0 branch

[ivmai]

Probably same root cause.
Source: master (3939446)
Build: https://github.com/ivmai/bdwgc/actions/runs/11019026341/job/30600667442
Host: Linux/x86_64
Config: zig build -Dtarget=native -DBUILD_SHARED_LIBS=false -Dbuild_cord=true -Ddisable_handle_fork=false -Denable_cplusplus=true -Denable_gc_assertions=true -Denable_gc_debug=true -Denable_large_config=false -Denable_munmap=false -Denable_parallel_mark=true -Denable_redirect_malloc=true -Denable_rwlock=true -Denable_thread_local_alloc=true -Denable_threads=true -Denable_werror test
Fail in weaktestmap