RE: [RFC PATCH] x86, entry: Switch stacks on a paranoid entry from userspace

[Luck, Tony]

> So far, the only thing I've come up with is that do_machine_check
> seems to be missing exception_enter or the equivalent.  Do you have
> CONFIG_CONTEXT_TRACKING on and/or full nohz enabled?  I don't think
> that this explains my bug, though.

Yes to both:

$ grep CONTEXT_TRACK .config
CONFIG_CONTEXT_TRACKING=y
# CONFIG_CONTEXT_TRACKING_FORCE is not set
CONFIG_HAVE_CONTEXT_TRACKING=y

$ grep HZ .config
CONFIG_NO_HZ_COMMON=y
# CONFIG_HZ_PERIODIC is not set
# CONFIG_NO_HZ_IDLE is not set
CONFIG_NO_HZ_FULL=y
# CONFIG_NO_HZ_FULL_ALL is not set
# CONFIG_NO_HZ_FULL_SYSIDLE is not set
CONFIG_NO_HZ=y
# CONFIG_RCU_FAST_NO_HZ is not set
# CONFIG_HZ_100 is not set
# CONFIG_HZ_250 is not set
# CONFIG_HZ_300 is not set
CONFIG_HZ_1000=y
CONFIG_HZ=1000
CONFIG_MACHZ_WDT=m

-Tony