From: Florian Weimer via Libc-alpha <libc-alpha@sourceware.org>
To: Carlos O'Donell <carlos@redhat.com>
Cc: Pedro Alves <palves@redhat.com>,
Daniel Walker via Libc-alpha <libc-alpha@sourceware.org>,
Conan C Huang <conhuang@cisco.com>,
Jeremy Stenglein <jstengle@cisco.com>,
xe-linux-external@cisco.com
Subject: Re: [RFC PATCH 3/3] add r_debug multiple namespaces support
Date: Fri, 26 Jun 2020 23:24:21 +0200 [thread overview]
Message-ID: <87366h5xmi.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <210c992f-b034-3ef7-440c-f67ab1b3acdb@redhat.com> (Carlos O'Donell's message of "Fri, 26 Jun 2020 17:19:27 -0400")
* Carlos O'Donell:
> On 6/26/20 5:05 PM, Florian Weimer via Libc-alpha wrote:
>> * Daniel Walker via Libc-alpha:
>>
>>> diff --git a/elf/link.h b/elf/link.h
>>> index 0048ad5d4d..5a42511636 100644
>>> --- a/elf/link.h
>>> +++ b/elf/link.h
>>> @@ -61,6 +61,10 @@ struct r_debug
>>> } r_state;
>>>
>>> ElfW(Addr) r_ldbase; /* Base address the linker is loaded at. */
>>> +
>>> + /* Link to next r_debug struct. Each r_debug struct represents a
>>> + different namespace. The first r_debug struct is the default. */
>>> + struct r_debug *next;
>>> };
>>>
>>> /* This is the instance of that structure used by the dynamic linker. */
>>
>> How has this patch been tested? I expect that it will cause an abilist
>> mismatch for the _r_debug symbol in the dynamic linker.
>>
>> If we go this route to add this capability, I think we have to add a new
>> symbol version for the _r_debug symbol, and keep the old one at the
>> previous size.
>>
>> How is your compatibility experience with the size and version change?
>> How many tools need updating before they work again?
>>
>> A different approach would add another symbol (parallel to _r_debug) to
>> store this data. This would avoid the need for any immediate tool
>> updates.
>
> I mention this in my response to the cover letter in this series.
Your explanation there was truncated.
> This patch is probably unacceptable as-is because of application
> expectations.
But perhaps Cisco's experience shows that our worries are unfounded?
Thanks,
Florian
next prev parent reply other threads:[~2020-06-26 21:24 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-26 19:32 [RFC PATCH 3/3] add r_debug multiple namespaces support Daniel Walker via Libc-alpha
2020-06-26 21:05 ` Florian Weimer via Libc-alpha
2020-06-26 21:19 ` Carlos O'Donell via Libc-alpha
2020-06-26 21:24 ` Florian Weimer via Libc-alpha [this message]
2020-06-26 21:44 ` Carlos O'Donell via Libc-alpha
2020-06-27 9:34 ` Florian Weimer
2020-06-28 12:34 ` Carlos O'Donell via Libc-alpha
2020-06-29 8:51 ` Florian Weimer via Libc-alpha
2021-07-23 23:38 ` H.J. Lu via Libc-alpha
2021-07-27 17:39 ` Daniel Walker via Libc-alpha
2021-07-27 18:14 ` H.J. Lu via Libc-alpha
2021-07-28 15:15 ` H.J. Lu via Libc-alpha
2021-07-28 15:44 ` Daniel Walker via Libc-alpha
2021-07-28 17:14 ` H.J. Lu via Libc-alpha
2021-07-28 19:02 ` Daniel Walker via Libc-alpha
2021-07-28 20:04 ` H.J. Lu via Libc-alpha
2021-08-02 4:24 ` RFC: Add DT_GNU_DEBUG H.J. Lu via Libc-alpha
2021-08-02 5:22 ` Florian Weimer via Libc-alpha
2021-08-02 13:10 ` H.J. Lu via Libc-alpha
2021-08-03 16:39 ` Daniel Walker via Libc-alpha
2021-08-03 18:08 ` H.J. Lu via Libc-alpha
2021-08-03 20:04 ` Daniel Walker via Libc-alpha
2021-08-03 18:12 ` Florian Weimer via Libc-alpha
2021-08-03 18:23 ` H.J. Lu via Libc-alpha
2021-08-03 20:13 ` Florian Weimer via Libc-alpha
2021-08-03 20:21 ` H.J. Lu via Libc-alpha
2021-08-09 14:32 ` RFC: 2 choices of DT_XXX for dlmopen H.J. Lu via Libc-alpha
2021-08-09 17:16 ` Daniel Walker via Libc-alpha
2021-08-15 0:33 ` [PATCH] Extend struct r_debug to support multiple namespaces H.J. Lu via Libc-alpha
2021-08-16 16:20 ` Daniel Walker via Libc-alpha
2021-08-17 1:07 ` H.J. Lu via Libc-alpha
2020-06-27 1:21 ` [RFC PATCH 3/3] add r_debug multiple namespaces support Daniel Walker (danielwa) via Libc-alpha
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