From: Florian Weimer <fweimer@redhat.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: "H.J. Lu via Libc-alpha" <libc-alpha@sourceware.org>,
Binutils <binutils@sourceware.org>
Subject: Re: RFC: Add GNU_PROPERTY_1_GLIBC_2_NEEDED
Date: Thu, 28 Oct 2021 08:55:38 +0200 [thread overview]
Message-ID: <87v91hljth.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <CAMe9rOrgC0F3Ox8+VkW8H62iCeNpsU_p6SuMsv9vdk7_Y1=9CQ@mail.gmail.com> (H. J. Lu's message of "Tue, 26 Oct 2021 08:51:29 -0700")
* H. J. Lu:
>> This proposal may conflict in spirit with the glibc proposal to support
>> preloadable symbol version (so you can add _dl_find_eh_frame@GLIBC_2.35
>> to a glibc 2.28 installation, for example). So far, symbol versions
>
> Why will adding a glibc version dependency change the preload
> behavior?
Previously, we thought we could relax the version coverage check to
enable adding completely new symbol versions by preloading an
implementation. With BIND_NOW, this is completely safe because missing
symbols are still detected. But this turns unreliable once glibc
versions are tied to ELF implementation features. Preloading an
implementation of _dl_find_eh_frame@GLIBC_2.35 (for example) will not
add dynamic linker features first implemented in glibc 2.35.
>> The problem that linkers and loaders ignore unknown types should be
>> tackled in a different way, e.g. by flagging critical types in some way.
>> See:
>>
>> Critical program headers and dynamic tags
>> <https://groups.google.com/g/generic-abi/c/vdG_G4l3N-Y/m/SB3DurdbBAAJ>
>>
>
> This won't help the existing ld.so binaries which this proposal
> is addressing.
We need to increase the ABI version once, to signal the requirement for
critical tags checking.
Thanks,
Florian
next prev parent reply other threads:[~2021-10-28 6:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-26 14:53 H.J. Lu
2021-10-26 15:25 ` Florian Weimer
2021-10-26 15:51 ` H.J. Lu
2021-10-26 18:39 ` v2: " H.J. Lu
2021-10-28 6:55 ` Florian Weimer [this message]
2021-10-28 13:37 ` H.J. Lu
2021-10-28 14:08 ` Florian Weimer
2021-10-28 14:17 ` H.J. Lu
2021-10-28 14:20 ` H.J. Lu
2021-10-29 18:11 ` Florian Weimer
2021-10-29 12:47 ` Michael Matz
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