[PATCH 0/2] Predictable ELF destructor ordering

[Stafford Horne]

On Tue, Dec 14, 2021 at 10:01:57PM +0100, Florian Weimer via Libc-alpha wrote:
> These patches remove the dependency sorting from dlclose and process
> shutdown, so that destructor order is the reverse of constructor order
> in more cases (always if the process does not call dlclose).
> 
> Tested on i686-linux-gnu and x86_64-linux-gnu.
> 
> I would like to include this in glibc 2.35 if possible, among the other
> dependency sorting changes.
> 
> I believe this fixes bugs 15311 and 15903.
> 
> Florian Weimer (2):
>   elf: Do not rely on relocation dependencies for destructor sorting
>   elf: Always call destructors in reverse constructor order
> 
>  elf/dl-close.c             | 130 +++++++++++++---------
>  elf/dl-deps.c              |   3 +-
>  elf/dl-fini.c              | 216 ++++++++++++++-----------------------
>  elf/dl-init.c              |  14 +++
>  elf/dl-sort-maps.c         | 105 ++----------------
>  elf/dso-sort-tests-1.def   |   6 +-
>  include/link.h             |   4 +
>  sysdeps/generic/ldsodefs.h |   6 +-
>  8 files changed, 194 insertions(+), 290 deletions(-)

Hi Florian,

This does seem to fix an issue for me in the OpenRISC port.  Discussed [1] in
the OpenRISC port thread.  It fixes:

  elf/tst-bz15311

Failure details in tst-bz15311.out (fixed with these patches) [2].

However this also seems to break:

  elf/tst-glibc-hwcaps-prepend-cache

I am not able to get much detail from the failure other than a SIGDEGV in fork,
I then bisected it to these patches I have on my branch to fix elf/tst-bz15311.
Let me know if I can help.

-Stafford

[1] https://sourceware.org/pipermail/libc-alpha/2021-December/134184.html
[2] https://gist.github.com/5a5dacaeef1eac1f2f5d89701d14c0ad