On Tue, Mar 26, 2019 at 05:36:06PM +0100, Thomas Gleixner wrote: > The SMT disable 'nosmt' command line argument is not working properly when > CONFIG_HOTPLUG_CPU is disabled. The teardown of the sibling CPUs which are > required to be brought up due to the MCE issues, cannot work. The CPUs are > then kept in a half dead state. > > As the 'nosmt' functionality has become popular due to the speculative > hardware vulnerabilities, the half torn down state is not a proper solution > to the problem. > > Enforce CONFIG_HOTPLUG_CPU=y when SMP is enabled so the full operation is > possible. > > Reported-by: Tianyu Lan <[email protected]> > Signed-off-by: Thomas Gleixner <[email protected]> > Cc: Konrad Wilk <[email protected]> > Cc: Josh Poimboeuf <[email protected]> > Cc: Mukesh Ojha <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Jiri Kosina <[email protected]> > Cc: Rik van Riel <[email protected]> > Cc: Andy Lutomirski <[email protected]> > Cc: Micheal Kelley <[email protected]> > Cc: K. Y. Srinivasan <[email protected]> > Cc: Greg KH <[email protected]> > Cc: Linus Torvalds <[email protected]> > Cc: Borislav Petkov <[email protected]> > Cc: [email protected] > --- > arch/x86/Kconfig | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-)
Acked-by: Greg Kroah-Hartman <[email protected]>
