Warnings about dlclose before thread exit

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Hi,

I've have upgraded to FreeBSD ALPHA 12.0, but I don't think the errors them from there. Although they could be in one of the libs that came along with the upgrade.

I'm getting these warnings during rbd and ceph (maybe even more) invocations that indicate that indicate a possible problem because:
===
   It could be possible that a dynamically loaded library, use
   thread_local variable but is dlclose()'d before thread exit.  The
   destructor of this variable will then try to access the address,
   for calling it but it's unloaded, so it'll crash.  We're using
   __elf_phdr_match_addr() to detect and prevent such cases and so
   prevent the crash.
===
this is from : https://github.com/freebsd/freebsd/blob/master/lib/libc/stdlib/cxa_thread_atexit_impl.c

Now it could be that dlclose() and thread exit are just closed to one another. But still this is hard core embedded in libc already since 2017, so I'm sort of expecting that a recent change has caused this.

And as indicated it is a possible cause for crashed, because thread_exit is going to clean up things that are no longer there.

Now the 20 dollar question is:
	Where was this introduced??

Otherwise I'll have to try and throw my best gdb capabilities at it, and try to invoke an rbd call and see where it activates this warning.

--WjW



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