REGRESSION: boot stalls on several old dual core Intel CPUs

[Siegfried Metz]

Dear kernel developers,

since mainline kernel 4.18 (up to the latest mainline kernel 4.18.5)
Intel Core 2 Duo processors are affected by boot stalling early in the
boot process. As it is so early there is no dmesg output (or any log).

A few users in the Arch Linux community used git bisect and tracked the
issue down to this the bad commit:
7197e77abcb65a71d0b21d67beb24f153a96055e clocksource: Remove kthread

Either reverting the bad commit or as a workaround using an additional
kernel boot parameter "clocksource=hpet" has been successfully used to
boot with Intel Core 2 processors and avoid the stalling.

clocksource= options parameters are one of "tsc", "hpet", "acpi_pm",
most of the time hpet did the trick.


Additional information:
Kernel 4.17.19 is unaffected by this issues, kernel 4.18 series and
4.19-rc1 are still affected.

Also there is the bug-report:
https://bugzilla.kernel.org/show_bug.cgi?id=200957
and a duplicate one:
https://bugzilla.kernel.org/show_bug.cgi?id=200959


Thanks for fixing this issue.

Siegfried