32-bit tool.drcacheoff.burst_threads fails with "Failed to take over all threads after multiple attempts"

This happens on my Debian-ish laptop:

291:   pre-DR start
291: 
291:   pre-DR detach
291: 
291:   pre-DR init
291: 
291:   pre-DR start
291: 
291:   <Application
291:   build_x86_dbg_tests/clients/bin32/tool.drcacheoff.burst_threads
291:   (2621379).  Failed to take over all threads after multiple attempts.>