[PATCH][BZ #19329] Fix race between tls allocation at thread creation and dlopen

[Torvald Riegel]

On Tue, 2016-01-12 at 14:28 +0000, Szabolcs Nagy wrote:
> tl;dr: if your libc has non-noop dlclose it must use a
> global lock in dlopen/dlclose/thread creation/tls access
> and user code must not run while that lock is held
> (e.g. signals must be blocked)

Depending on what the non-noop functionality is, it might be possible to
still implement this in a nonblocking way (so you avoid the blocking
sync vs. signals and reentrancy issue).