[PATCH v3] elf: Test dlopen (NULL, RTLD_LAZY) from an ELF constructor

[Sam James]

Florian Weimer <fweimer@redhat.com> writes:

> * Florian Weimer:
>
>> This call must not complete initialization of all shared objects
>> in the global scope because the ELF constructor which makes the call
>> likely has not finished initialization.  Calling more constructors
>> at this point would expose those to a partially constructed
>> dependency.
>>
>> This completes the revert of commit 9897ced8e78db5d813166a7ccccfd5a
>> ("elf: Run constructors on cyclic recursive dlopen (bug 31986)").
>>
>> ---
>> v3: Repost to resolve Makefile conflict.
>>  elf/Makefile                           |  9 ++++++
>>  elf/dl-open.c                          | 10 +++++++
>>  elf/tst-dlopen-constructor-null-mod1.c | 55 ++++++++++++++++++++++++++++++++++
>>  elf/tst-dlopen-constructor-null-mod2.c | 37 +++++++++++++++++++++++
>>  elf/tst-dlopen-constructor-null.c      | 38 +++++++++++++++++++++++
>>  5 files changed, 149 insertions(+)
>
> Could I get a review for this, please?  I think it addresses a real
> testing gap.

I left some small comments. I don't feel qualified enough in this area
to say I could spot a testing issue (which is why I hadn't commented),
but it looks okay apart from what I pointed out.