For reference: While debugging this very tricky problem, our kernel team found 2 separate but related bugs whose resolutions fix the problem outlined in this report. The bug fixes both resulted in CVEs and have already been added to Linus' tree. They are: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=fixes&id=a8318c13e79badb92bc6640704a64cc022a6eb97 https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=fixes&id=8205d5d98ef7f155de211f5e2eb6ca03d95a5a60 The CVEs are: https://security-tracker.debian.org/tracker/CVE-2019-15030 https://security-tracker.debian.org/tracker/CVE-2019-15031 One of the problems was introduced in 4.12, and the other in 4.15. Barry
- Bug#866122: kernel resolution Barry Arndt
- Bug#866122: kernel resolution Ryan Tandy