Are vDSO addresses special?

[Florian Weimer]

In glibc, we have some code that copies the DT_SONAME string of the
kernel vDSO into the heap, commented this way:

             /* Work around a kernel problem.  The kernel cannot handle
                addresses in the vsyscall DSO pages in writev() calls.  */

Is this really a problem anymore?  vDSO addresses are ordinary userspace
addresses, I think.  (The vsyscall stuff is very different, of course,
and maybe the vDSO started out the same way.)

We only care about Linux 3.2 or later in glibc.

Thanks,
Florian
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