Debugging containerized glibc tests with gdb (a developer use case for outside-of-container debugging).

Carlos O'Donell carlos@redhat.com
Sat Jan 4 14:30:00 GMT 2020


On 12/27/19 12:55 PM, Gabriel F. T. Gomes wrote:
> Hi, Carlos,
> 
> On Fri, 27 Dec 2019, Carlos O'Donell wrote:
>>
>> Did you try --enable-hardcoded-path-in-tests?
> 
> I hadn't. ¬¬
> That was it.

Interesting! Thank you for looking into this more deeply.

Reproducing these issues is half the battle!

> You wrote this in your first email:
> 
>> In test-container.c we mount $srcdir and $objdir into the same absolute paths
>> inside the container, so ld.so should be accessible from the same absolute paths.
>> If we fail those mounts we immediately fail the test with FAIL_EXIT1.
> 
> I think the paths are the same, but the contents are not identical.  On
> the tests I did, the testroot.root/path/to/build/dir/elf directory is
> missing the symlink between ld.so and ld<whatever>.so.<n>.  For instance:

Are you saying the contents of $objdir's mount in the sysroot are not the same
as the contents of $objdir as seen _outsite_ of the sysroot?

We have two paths:

- Normal $objdir
- $objdir as seen from within the sysroot's mount

 
>   $ ls -l testroot.root/home/gabriel/build/x86_64/glibc/elf
>   -rwxrwxr-x 1 gabriel gabriel 1342800 Dec 27 11:09 ld-linux-x86-64.so.2

A normal $objdir should have:

lrwxrwxrwx.  1 carlos carlos       5 Aug  1 00:51 ld-linux-x86-64.so.2 -> ld.so
-rwxrwxr-x.  1 carlos carlos 1458696 Aug  1 00:51 ld.so

>   $ ls -l testroot.root/home/gabriel/build/powerpc64le/glibc/elf/
>   -rwxr-xr-x 1 gabriel gabriel 1566232 Dec 27 09:05 ld64.so.2

Likewise.

> Whereas on the actual build dir:
 
>   $ ls -l elf/ld*.so*
>   lrwxrwxrwx 1 gabriel gabriel       5 Dec 27 09:04 elf/ld64.so.2 -> ld.so
>   -rwxr-xr-x 1 gabriel gabriel 1566232 Dec 27 09:04 elf/ld.so

Yes, this is correct.

>> warning: Could not load shared library symbols for /home/carlos/build/glibc-gr-localedef/elf/ld.so.
> 
> If I create the ld.so symlink in the sysroot, the problem goes away.
> Should there be a symlink in the sysroot?
 
Why would we need to create it? I thought this path was simply
a MS_BIND mount of the $objdir and should have identical contents?

-- 
Cheers,
Carlos.



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