Bug #1795857 reported by Timo Aaltonen on 2018-10-03
This bug affects 2 people
Affects Status Importance Assigned to Milestone
kmod (Ubuntu)
linux (Ubuntu)

Bug Description

CONFIG_DRM_BOCHS got disabled for https://bugs.launchpad.net/ubuntu/+source/kmod/+bug/1378648

but doing so regressed running qemu with the 'std' VGA driver, where it'd fail to start X after install, as mentioned on bug 1794280

CVE References

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1795857

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

Changed in linux (Ubuntu):
status: New → Incomplete
Timo Aaltonen (tjaalton) on 2018-10-03
Changed in linux (Ubuntu):
status: Incomplete → Confirmed
Ubuntu QA Website (ubuntuqa) wrote :

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:

tags: added: iso-testing
Thomas Lamprecht (t-lamprecht) wrote :

I've send a patch for the kernel part of this request:

Additionally to it the kmod's "blacklist bochs-drm" entry from it's /etc/modprobe.d/blacklist-framebuffer.conf file it ships would need to get removed.

With this I can successfully start VMs wit stdvga as display under QEMU and/or QEMU/KVM again.
Without this it's completely broken, but note that the installation itself works, you'll only see the issues after you boot in the fresh installed system.

Adam Conrad (adconrad) wrote :

The original bug report was on PowerKVM (ppc64el qemu). In testing that it was okay to revert this wholesale in both kmod and kernel, did anyone test POWER?

Adam Conrad (adconrad) wrote :

I'm rejecting the kmod upload in the disco queue until the above comment is addressed, so we don't get into a revert war.

I have tested that the module loads and works fine on POWER, on a KVM guest on top of a Power8 system.

Adam Conrad (adconrad) wrote :

What was the host system (ie: what version of qemu)? I want to be sure this works going back as far as we support (so, trusty hosts).

Timo Aaltonen (tjaalton) on 2019-04-01
Changed in linux (Ubuntu):
status: Confirmed → Incomplete
Timo Aaltonen (tjaalton) wrote :

t-lamprecht/cascardo: are you able to reply to adam's question, so that this could be enabled across the board and not just on !ppc?

Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in kmod (Ubuntu):
status: New → Confirmed

Thanks cascardo for testing power8 already.

This came up in bug 1823152 as well and made me aware of this.
If qemu is not run in commandline most frontends set something else than "-vga std" therefore I wasn't aware. But I can confirm seeing the issue.

I think I can test x86 quite easily, is there a PPA to test this?
Actually everyone can:
1. sudo qemu-img create /var/lib/libvirt/images/xubuntu18_04.qcow2 15G
2. sudo qemu-system-x86_64-spice -enable-kvm -cpu host -boot d -cdrom ~/Downloads/xubuntu-18.04.2-desktop-amd64.iso /var/lib/libvirt/images/xubuntu18_04.qcow2 -m 8G
3. sudo qemu-system-x86_64-spice -enable-kvm -cpu host /var/lib/libvirt/images/xubuntu18_04.qcow2 -m 8G

#3 fails with the default, set "-vga qxl" and you have a working guest.
For mass testing you can do the install in #2 once and then just copy around the image file to boot e.g. under different Hosts versions.

OTOH - I'm not sure I can speak for all potential implications as the kmod header reads like:
"# Framebuffer drivers are generally buggy and poorly-supported, and cause
# suspend failures, kernel panics and general mayhem. For this reason we
# never load them automatically."
I won't test e.g. suspend on all of them and/or might it be an issue on bare metal or on real Bochs?

See lightdm and gpu-manager services in http://paste.ubuntu.com/p/5QyzgMKhmr/ for an example how that looks like from a guests POV.

Timo Aaltonen (tjaalton) wrote :

right, so OTOH the old regression on ppc hasn't been fully verified yet, but blacklisting bochs_drm causes 1823152 on x86 which surely is more important than ppc..

@Timo - Ack, this should be enabled again. And if really still an issue for PPC then a different solution than to disable it should be evaluated (can we do arch specific blakclisting?).

Timo Aaltonen (tjaalton) wrote :

the disco kernel being prepared does enable bochs again, but kmod still needs to be fixed.. there's no mechanism for arch-specific blacklisting (right now at least), but the kernel option could still be disabled for ppc if absolutely necessary

Launchpad Janitor (janitor) wrote :

This bug was fixed in the package kmod - 25-1ubuntu4

kmod (25-1ubuntu4) disco; urgency=medium

  * Drop bochs-drm from the blacklist. (LP: #1795857)

 -- Timo Aaltonen <email address hidden> Fri, 12 Apr 2019 11:23:05 +0300

Changed in kmod (Ubuntu Disco):
status: Confirmed → Fix Released
Launchpad Janitor (janitor) wrote :
Download full text (50.5 KiB)

This bug was fixed in the package linux - 5.0.0-11.12

linux (5.0.0-11.12) disco; urgency=medium

  * linux: 5.0.0-11.12 -proposed tracker (LP: #1824383)

  * hns3: PPU_PF_ABNORMAL_INT_ST over_8bd_no_fe found [error status=0x1]
    (LP: #1824194)
    - net: hns3: fix for not calculating tx bd num correctly

  * disco: unable to use iptables/enable ufw under -virtual kernel
    (LP: #1823862)
    - [Packaging] add bpfilter to linux-modules

  * Make shiftfs a module rather than built-in (LP: #1824354)
    - [Config] CONFIG_SHIFT_FS=m

  * shiftfs: chown sets untranslated ids in lower fs (LP: #1824350)
    - SAUCE: shiftfs: use translated ids when chaning lower fs attrs

  * [Hyper-V] KVP daemon fails to start on first boot of disco VM (LP: #1820063)
    - [Packaging] bind hv_kvp_daemon startup to hv_kvp device

linux (5.0.0-10.11) disco; urgency=medium

  * linux: 5.0.0-10.11 -proposed tracker (LP: #1823936)

  * Apparmor enforcement failure in lxc selftests (LP: #1823379)
    - SAUCE: apparmor: Restore Y/N in /sys for apparmor's "enabled"

  * systemd cause kernel trace "BUG: unable to handle kernel paging request at
    6db23a14" on Cosmic i386 (LP: #1813244)
    - openvswitch: fix flow actions reallocation

linux (5.0.0-9.10) disco; urgency=medium

  * linux: 5.0.0-9.10 -proposed tracker (LP: #1823228)

  * Packaging resync (LP: #1786013)
    - [Packaging] resync git-ubuntu-log
    - [Packaging] update helper scripts
    - [Packaging] resync retpoline extraction

  * Huawei Hi1822 NIC has poor performance (LP: #1820187)
    - net-next/hinic: replace disable_irq_nosync/enable_irq

  * Add uid shifting overlay filesystem (shiftfs) (LP: #1823186)
    - shiftfs: uid/gid shifting bind mount
    - shiftfs: rework and extend
    - shiftfs: support some btrfs ioctls
    - [Config] enable shiftfs

  * Cannot boot or install - have to use nomodeset (LP: #1821820)
    - Revert "drm/i915/fbdev: Actually configure untiled displays"

  * Disco update: v5.0.6 upstream stable release (LP: #1823060)
    - netfilter: nf_tables: fix set double-free in abort path
    - dccp: do not use ipv6 header for ipv4 flow
    - genetlink: Fix a memory leak on error path
    - gtp: change NET_UDP_TUNNEL dependency to select
    - ipv6: make ip6_create_rt_rcu return ip6_null_entry instead of NULL
    - mac8390: Fix mmio access size probe
    - mISDN: hfcpci: Test both vendor & device ID for Digium HFC4S
    - net: aquantia: fix rx checksum offload for UDP/TCP over IPv6
    - net: datagram: fix unbounded loop in __skb_try_recv_datagram()
    - net/packet: Set __GFP_NOWARN upon allocation in alloc_pg_vec
    - net: phy: meson-gxl: fix interrupt support
    - net: rose: fix a possible stack overflow
    - net: stmmac: fix memory corruption with large MTUs
    - net-sysfs: call dev_hold if kobject_init_and_add success
    - net: usb: aqc111: Extend HWID table by QNAP device
    - packets: Always register packet sk in the same order
    - rhashtable: Still do rehash when we get EEXIST
    - sctp: get sctphdr by offset in sctp_compute_cksum
    - sctp: use memdup_user instead of vmemdup_user
    - tcp: do not use ipv6 header for ipv4 flow
    - tipc: allow servic...

Changed in linux (Ubuntu Disco):
status: Incomplete → Fix Released

Thank you Timo!

flumm (dominik-csapak) wrote :

just fyi, this also affects newer iso releases of 18.04 (e.g. 18.04.2)
i suspect the new xorg in the hwe version needs the bochs drm module

Brad Figg (brad-figg) on 2019-07-24
tags: added: cscc
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