i686 4G/4G sysenter vDSO handles only 5 syscalls and special-cases mmap2. Unfortunately, this is not the only 6 argument syscall on IA-32. E.g. fadvise64_64 has 6 arguments too, there might be others. I wonder if it is not possible to instead just do the get_user part in sysenter_entry before switching page tables and deal with the possible fault in the trap handler.
Of course I meant "handles only 5 argument syscalls"...
Is this a issue for any non-i686 arch? Since FC4 ships without 4G/4G, shouldn't this be FC5 instead of FC4 target?
closing this bug - it seems glibc is now working this around by always doing int80 for fadvise64_64.