commit fed8d8773b8ea68ad99d9eee8c8343bef9da2c2c upstream. The logic in acpi_is_processor_usable() requires the online capable bit be set for hotpluggable CPUs. The online capable bit has been introduced in ACPI 6.3. However, for ACPI revisions < 6.3 which do not support that bit, CPUs should be reported as usable, not the other way around. Reverse the check. [ bp: Rewrite commit message. ] Fixes: e2869bd7af60 ("x86/acpi/boot: Do not register processors that cannot be onlined for x2APIC") Suggested-by: Miguel Luis <miguel.luis@oracle.com> Suggested-by: Boris Ostrovsky <boris.ovstrosky@oracle.com> Signed-off-by: Eric DeVolder <eric.devolder@oracle.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Tested-by: David R <david@unsolicited.net> Cc: <stable@kernel.org> Link: https://lore.kernel.org/r/20230327191026.3454-2-eric.devolder@oracle.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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