On 12/19/18 4:25 PM, Ken Pizzini wrote: > Since 4.19.5 I have not been able to boot kernels on my Xen-hosted VM on > a system with an Intel Xeon L5520 processor (microcode 0x1d). > > 4.19.4 worked fine; I've tried kernels 4.19.5, 4.19.6, 4.19.7 4.19.9, 4.19.10, > 4.20-rc7, and they all throw: > BUG: unable to handle kernel paging request at ffff88903fffc000 > PGD 1c0c067 P4D 1c0c067 PUD 0 > Oops: 0000 [#1] PREEMPT SMP NOPTI > ... [register dump and call trace omitted, since I believe I located the > offending source code] > Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 > Kernel Offset: disabled > early in the system boot (fine details might differ; I did not carefully > record the result of each test). > > I finally had time to do some bisection, and the problem traces back to commit > d52888aa2753e3063a9d3a0c9f72f94aa9809c15 > in tree fbbb33771ac6c392caeb283163a594f1a7e6d04d > (x86/mm: Move LDT remap out of KASLR region on 5-level paging). > > After backing-out this one commit, I have successfully built and booted > 4.19.5, 4.19.10 and 4.20-rc7 (I haven't bothered trying other versions). > (The VM is currently running my patched 4.19.10 without any apparent problem.) > > Notes: all 4.19.* builds are of Gentoo's "gentoo-sources" tree (which include > standard Gentoo patches), plus wireguard; the 4.20-rc7 build was unpatched. > I have been successfully running a different build of each 4.19.* version > on my laptop (with many more device drivers enabled), so the problem > is unlikely to be due to the build toolchain (which is common to both > of my build trees). > > > Let me know if there is more information that you would find helpful, > or if you have patches that you'd like me to test. > > --Ken Pizzini
This is addressed by https://lkml.org/lkml/2018/12/11/266 but has not been merged yet. (Next time for Xen issues please copy xen-de...@lists.xenproject.org) -boris
