Re: [PATCH] dlopen: Fix issues related to NODELETE handling and relocations

[Florian Weimer <fweimer at redhat dot com>]

* Florian Weimer:

> The assumption behind the assert in activate_nodelete was wrong:
>
> Inconsistency detected by ld.so: dl-open.c: 459: activate_nodelete:
> Assertion `!imap->l_init_called || imap->l_type != lt_loaded' failed! (edit)
>
> It can happen that an already-loaded object that is in the local
> scope is promoted to NODELETE status, via binding to a unique
> symbol.
>
> Similarly, it is possible that such NODELETE promotion occurs to
> an already-loaded object from the global scope.  This is why the
> loop in activate_nodelete has to cover all objects in the namespace
> of the new object.
>
> In do_lookup_unique, it could happen that the NODELETE status of
> an already-loaded object was overwritten with a pending NODELETE
> status.  As a result, if dlopen fails, this could cause a loss of
> the NODELETE status of the affected object, eventually resulting
> in an incorrect unload.
>
> Fixes commit f63b73814f74032c0e5d0a83300e3d864ef905e5 ("Remove all
> loaded objects if dlopen fails, ignoring NODELETE [BZ #20839]").
>
> Tested on x86_64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu.

Ping.  This patch needs review.  It fixes a couple of regressions in the
dlopen NODELETE changes.

  <https://sourceware.org/ml/libc-alpha/2019-12/msg00098.html>

Thanks,
Florian