[Bug dynamic-link/27104] New: The COMMON_CPUID_INDEX_MAX handshake does not work

[Bug dynamic-link/27104] New: The COMMON_CPUID_INDEX_MAX handshake does not work

[hjl.tools at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27104

            Bug ID: 27104
           Summary: The COMMON_CPUID_INDEX_MAX handshake does not work
           Product: glibc
           Version: 2.33
            Status: NEW
          Severity: normal
          Priority: P2
         Component: dynamic-link
          Assignee: unassigned at sourceware dot org
          Reporter: hjl.tools at gmail dot com
  Target Milestone: ---
            Target: i386,x86-64

__x86_get_cpu_features returns NULL if its argument is too large.  This
effectively disables *all* feature bits, not just those beyond
COMMON_CPUID_INDEX_MAX. This means that if you build with a header that
is too new, an application may fail due to the lack of detected features
when running on an older glibc version.  Ideally, only the newly added
CPU features would be detected as missing in this scenario.  Simply
recompiling an application with a newer header should not result in any
detection changes.

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[Bug dynamic-link/27104] The COMMON_CPUID_INDEX_MAX handshake does not work

[hjl.tools at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27104

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |2.33
                 CC|                            |fw at deneb dot enyo.de

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> ---
A patch is posted at

https://sourceware.org/pipermail/libc-alpha/2020-December/120968.html

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[Bug dynamic-link/27104] The COMMON_CPUID_INDEX_MAX handshake does not work

[hjl.tools at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27104

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> ---
The updated patch is at

https://patchwork.sourceware.org/project/glibc/patch/20201225162451.1657088-1-hjl.tools@gmail.com/

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[Bug dynamic-link/27104] The COMMON_CPUID_INDEX_MAX handshake does not work

[hjl.tools at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27104

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> ---
Fixed for 2.33 by

commit ff6d62e9edb5dce537a6dd4a237d6053f331f09c
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Dec 25 07:30:46 2020 -0800

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