I suspect all kernel TLB entries need to be flushed prior to alternative patching to ensure that kernel pages are writeable. Was this a reboot or cold boot?
Reboot from 4.19.0. Next reboots from 4.19.0+git worked fine. Cold boot into 4.19-git workd fine too now. Will try if I can make it happen again when rebooting from 4.19.0 (maybe it has cached different pages in TLB to make a difference - but that may depend on the previous load). -- Meelis Roos <mroos@xxxxxxxx>
