Bug 2023420

Summary: glibc: Backport ld.so --list-diagnostics [rhel-8.6]
Product: Red Hat Enterprise Linux 8 Reporter: Florian Weimer <fweimer>
Component: glibcAssignee: Florian Weimer <fweimer>
Status: CLOSED ERRATA QA Contact: Martin Coufal <mcoufal>
Severity: unspecified Docs Contact: mtimar
Priority: unspecified    
Version: 8.6CC: ashankar, codonell, dj, fweimer, jvaldez, mcoufal, mnewsome, mtimar, pfrankli, sdodson, sipoyare
Target Milestone: rcKeywords: FutureFeature, Patch, Triaged
Target Release: 8.6Flags: pm-rhel: mirror+
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: glibc-2.28-179.el8 Doc Type: Enhancement
Doc Text:
.New command for capturing `glibc` optimization data The new `ld.so --list-diagnostics` command captures data that influences `glibc` optimization decisions, such as IFUNC selection and `glibc-hwcaps` configuration, in a single machine-readable file.
 Story Points: ---
Clone Of:
: 2023422 (view as bug list) Environment:
Last Closed: 2022-05-10 15:17:47 UTC Type: Enhancement
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2023422    
Bug Blocks:    
Deadline: 2021-12-27   

Description Florian Weimer 2021-11-15 16:46:53 UTC 
In order to transition to x86-64-v2 in Red Hat Enterprise Linux 9, better diagnostics for missing CPU support are desirable. We should backport these commits:

commit 851f32cf7bf7067f73b991610778915edd57d7b4
Author: Florian Weimer <fweimer>
Date:   Tue Mar 2 14:38:42 2021 +0100

    ld.so: Implement the --list-diagnostics option

commit 01a5746b6c8a44dc29d33e056b63485075a6a3cc
Author: Florian Weimer <fweimer>
Date:   Wed Feb 24 13:12:04 2021 +0100

    x86: Add CPU-specific diagnostics to ld.so --list-diagnostics

And we should consider installing a symbolic link /usr/bin/ld.so that points to the architecture dynamic loader, so that users can just run ld.so --help (or use other ld.so features) without worrying about the precise hardware/ABI supported by the system.
Comment 1 Florian Weimer 2021-11-15 18:28:20 UTC 
Upstream patch posted for the creation of /usr/bin/ld.so:

[PATCH] elf: Install a symbolic link to ld.so as /usr/bin/ld.so
https://sourceware.org/pipermail/libc-alpha/2021-November/133078.html
Comment 5 Martin Coufal 2021-12-15 10:11:28 UTC 
Tested on glibc-2.28-179.el8.
Comment 9 Martin Coufal 2021-12-15 10:39:01 UTC 
Verified on:
glibc-2.28-179.el8
RHEL-8.6.0-20211213.3

See test results in the attachments for details.
Comment 14 errata-xmlrpc 2022-05-10 15:17:47 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (glibc bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2022:2005