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From: "conanhc at gmail dot com" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug dynamic-link/25615] dlopen RTLD_NOLOAD optimization
Date: Wed, 13 Mar 2024 20:27:56 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D25615

Conan Huang <conanhc at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |INVALID

--- Comment #2 from Conan Huang <conanhc at gmail dot com> ---
Optimization breaks following scenario:

If we dlopen(library, RTLD_NOLOAD | RTLD_LAZY). If that library doesn't have
its local search scope already set up (l_local_scope). Then dlopen will set=
 it
up by calling  _dl_map_object_deps and going thru its dependencies.

With NOLOAD optimization patch, it'll skip _dl_map_object_deps, and not set=
up
l_local_scope.

If we call dlsym after dlopen(library, RTLD_NOLOAD), dynamic loader tries to
search that library's local scope for a definition. If l_local_scope is emp=
ty,
dynamic loader will segfault.

As a result, _dl_map_object_deps is needed to generate l_local_scope.

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