[Bug dynamic-link/30062] glibc 2.36 loader has intermittent segfault error on ppc64le

["carlos at redhat dot com" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=30062

Carlos O'Donell <carlos at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |carlos at redhat dot com
   Last reconfirmed|                            |2023-01-31
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Carlos O'Donell <carlos at redhat dot com> ---
(In reply to ChenQi from comment #0)
> Except the above backtrace and LD_DEBUG testing, I also done one more
> testing which made me believe the bug is in glibc.

The best bet here is to run with Valgrind and try to find the invalid access.

> I changed glibc to musl to check if it's the glibc's issue or not. The
> result is: when using musl, there's no segfault error. That's why I filed a
> bug here.

Musl's dynamic loader will never unload a library and calling dlclose() does
not run the library desctructors.

glibc's dynamic loader will attempt to run destructors and unload and unmap the
library.

Under glibc you must accurately account for any dangling references to the
library after unloading.

Thus I expect that this is related to the libraries you are loading and
unloading and their specific constructors and destructors.

I haven't seen any reports of this in Fedora 37, which uses glibc 2.36, and has
syslog-ng compiled for ppc64le.

> related syslog-ng issue link:
> https://github.com/syslog-ng/syslog-ng/issues/4285

Thanks. I commented there.

Next steps:
- Please run your reproducer under valgrind and see if you can determine the
root cause of the crash.

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