On Tue, May 29, 2018 at 01:56:29PM +1000, Michael Neuling wrote:
Clear the PCR (Processor Compatibility Register) on boot to ensure we are not running in a compatibility mode.
We've seen this cause problems when a crash (and kdump) occurs while running compat mode guests. The kdump kernel then runs with the PCR set and causes problems. The symptom in the kdump kernel (also seen in petitboot after fast-reboot) is early userspace programs taking sigills on newer instructions (seen in libc).
Signed-off-by: Michael Neuling mikey@neuling.org Cc: stable@vger.kernel.org # v4.9 Signed-off-by: Michael Ellerman mpe@ellerman.id.au --
Greg, This is a backport for v4.9 only since the original patch didn't apply.
Commit faf37c44a105f3608115785f17cbbf3500f8bc71 upstream.
Thanks for this, and the 4.4 backport, both now queued up.
greg k-h