From: Florian Weimer <fweimer@redhat.com>
To: Jacob Kroon <jacob.kroon@gmail.com>
Cc: Jacob Kroon via Gdb <gdb@sourceware.org>
Subject: Re: Debugging ld.so in gdb
Date: Mon, 07 Feb 2022 13:27:54 +0100 [thread overview]
Message-ID: <87wni6amk5.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <3e08e7c7-05f5-16f2-50cb-036687386997@gmail.com> (Jacob Kroon's message of "Mon, 7 Feb 2022 13:15:28 +0100")
* Jacob Kroon:
>> What I find really confusing is that this is not the result of a dlopen
>> call. I definitely would expect that the maps array contains *all*
>> objects that are being loaded. Clearly this is not the case here.
>> Somehow certain objects are missing, and then they get written into the
>> rpo array.
>>
>> Please try to find libjvm.so among the l_initfini arrays of the objects.
>
> I do find libjvm.so in a couple of the maps[]->l_initfini[]->l_name
> arrays, yes.
Okay, and of course there is an assumption that those make it to the
maps. No wonder we run off the array.
>> It must be present somewhere. I assume it's also on the main list,
>> which starts off at _rtld_global._dl_ns[0]._ns_loaded.
>
> Hmm how do I iterate over that data structure ?
>
> See below:
>> (gdb) print _rtld_global._dl_ns[0]._ns_loaded[0]->l_name
>> $186 = 0x7ffff7ff1d97 ""
>> (gdb) print _rtld_global._dl_ns[0]._ns_loaded[1]->l_name
>> $187 = 0x0
>> (gdb) print _rtld_global._dl_ns[0]._ns_loaded[2]->l_name
>> $188 = 0x0
>> (gdb) print _rtld_global._dl_ns[0]._ns_loaded->l_name
>> $189 = 0x7ffff7ff1d97 ""
>> (gdb) print _rtld_global._dl_ns[1]._ns_loaded->l_name
>> Cannot access memory at address 0x8
>> (gdb) print _rtld_global._dl_ns[2]._ns_loaded->l_name
>> Cannot access memory at address 0x8
It's a list chained by l_prev/l_next.
Thanks,
Florian
next prev parent reply other threads:[~2022-02-07 12:28 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-04 13:45 Jacob Kroon
2022-02-04 13:58 ` Florian Weimer
2022-02-04 14:09 ` Jacob Kroon
2022-02-04 14:22 ` Florian Weimer
2022-02-04 14:27 ` Jacob Kroon
2022-02-04 16:09 ` Florian Weimer
2022-02-04 16:53 ` Jacob Kroon
2022-02-04 17:04 ` Florian Weimer
2022-02-04 17:11 ` Jacob Kroon
2022-02-04 17:15 ` Florian Weimer
2022-02-07 8:36 ` Jacob Kroon
2022-02-07 11:46 ` Jacob Kroon
2022-02-07 11:55 ` Florian Weimer
2022-02-07 12:15 ` Jacob Kroon
2022-02-07 12:27 ` Florian Weimer [this message]
2022-02-07 12:32 ` Jacob Kroon
2022-02-07 13:39 ` Jacob Kroon
2022-02-07 13:45 ` Jacob Kroon
2022-02-07 13:53 ` Adhemerval Zanella
2022-02-07 13:54 ` Jacob Kroon
2022-02-07 14:07 ` Florian Weimer
2022-02-07 16:28 ` Florian Weimer
2022-02-07 17:04 ` Jacob Kroon
2022-02-04 14:45 ` Jacob Kroon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87wni6amk5.fsf@oldenburg.str.redhat.com \
--to=fweimer@redhat.com \
--cc=gdb@sourceware.org \
--cc=jacob.kroon@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).