> In conclusion, I’ll assume this is not a typical scenario and it is mostly safe.

Ughh, this brings bad memories of the days I spent trying to diagnose why glibc often would give wrong answers for some users and not other users (they’ve since mitigated this problem slightly by combining pthreads and libdl into the same library). I wish they would get rid of this, since even the comment on it notes that the optimization is unsound (the ability to make syscalls directly, as used by go and others, makes this optimization potentially dangerous). It also upsets static analysis tools, since they see that glibc doesn’t appear to have the synchronization the library promises.