[Bug libc/28784] x86: crash in 32bit memset-sse2.s when the cache size can not be determined

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=28784

--- Comment #5 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The release/2.33/master branch has been updated by Aurelien Jarno
<aurel32@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=a51b76b71e8190a50b0e0c0b32f313888b930108

commit a51b76b71e8190a50b0e0c0b32f313888b930108
Author: Aurelien Jarno <aurelien@aurel32.net>
Date:   Mon Jan 17 19:41:40 2022 +0100

    x86: use default cache size if it cannot be determined [BZ #28784]

    In some cases (e.g QEMU, non-Intel/AMD CPU) the cache information can
    not be retrieved and the corresponding values are set to 0.

    Commit 2d651eb9265d ("x86: Move x86 processor cache info to
    cpu_features") changed the behaviour in such case by defining the
    __x86_shared_cache_size and __x86_data_cache_size variables to 0 instead
    of using the default values. This cause an issue with the i686 SSE2
    optimized bzero/routine which assumes that the cache size is at least
    128 bytes, and otherwise tries to zero/set the whole address space minus
    128 bytes.

    Fix that by restoring the original code to only update
    __x86_shared_cache_size and __x86_data_cache_size variables if the
    corresponding cache sizes are not zero.

    Fixes bug 28784
    Fixes commit 2d651eb9265d

    Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
    (cherry picked from commit c242fcce06e3102ca663b2f992611d0bda4f2668)

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