race condition between vhost_net_stop and CHR_EVENT_CLOSED on shutdown crashes qemu (fix regression)

marking 'invalid' for newer qemu; this is fixed in a different way in newer qemu but the change is too large to backport; the patches for xenial (and mitaka/ocata) are a minimal workaround.

Hello Dan, or anyone else affected,

Accepted qemu into ocata-proposed. The package will build now and be available in the Ubuntu Cloud Archive in a few hours, and then in the -proposed repository.

Please help us by testing this new package. To enable the -proposed repository:

  sudo add-apt-repository cloud-archive:ocata-proposed
  sudo apt-get update

Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-ocata-needed to verification-ocata-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-ocata-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

The verification of the Stable Release Update for qemu has completed successfully and the package has now been released to -updates. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

This bug was fixed in the package qemu - 1:2.8+dfsg-3ubuntu2.9~cloud6
---------------

 qemu (1:2.8+dfsg-3ubuntu2.9~cloud6) xenial-ocata; urgency=medium
 .
   * SECURITY UPDATE: Add support for exposing md-clear functionality
     to guests
     - d/p/ubuntu/enable-md-clear.patch
     - CVE-2018-12126, CVE-2018-12127, CVE-2018-12130, CVE-2019-11091
   * SECURITY UPDATE: heap overflow when loading device tree blob
     - d/p/ubuntu/CVE-2018-20815.patch: specify how large the buffer to
       copy the device tree blob into is.
     - CVE-2018-20815
   * SECURITY UPDATE: information leak in SLiRP
     - d/p/ubuntu/CVE-2019-9824.patch: check sscanf result when
       emulating ident.
     - CVE-2019-9824
   * d/p/ubuntu/fix-virtio-net-regression.patch: Fix regression of failing qemu
     guest networking (LP: #1829380).

I'm currently prepping soem things for Xenials virtualization stack anyway.
I'll make this fixup (+reestablishign the original fix) part of it.

MP to review:
https://code.launchpad.net/~paelzer/ubuntu/+source/qemu/+git/qemu/+merge/367971

PPA to test:
https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/3729

ocata:

I was able to reproduce the regression by rebooting the guest - I could not reproduce it any other way, by attaching/removing interface(s), setting their link up/down from the host side or from the guest side, adding/removing them to a bridge on the host, etc. On reboot, with qemu 1:2.8+dfsg-3ubuntu2.9~cloud5.1, after 2 reboots I was able to reproduce the guest being unable to use the interface. I stopped the guest, upgraded to 1:2.8+dfsg-3ubuntu2.9~cloud6, and repeated the test, and the guest had no problems even after 10 reboots.

Hi
I wanted to mention that I have not found an issue on this in my regression testing running on this code against a PPA.
The qemu already in -unapproved is identical to what I proposed and we checked on - so lets keep it there as is to be accepted.

Hello Dan, or anyone else affected,

Accepted qemu into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/qemu/1:2.5+dfsg-5ubuntu10.40 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-xenial to verification-done-xenial. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-xenial. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

With qemu version 1:2.5+dfsg-5ubuntu10.37, I rebooted a guest with a normal network interface, and after the 2nd reboot it lost networking. Then upgraded to 1:2.5+dfsg-5ubuntu10.40, stopped and started guest, and rebooted it 10 times without any networking problems.

This bug was fixed in the package qemu - 1:2.5+dfsg-5ubuntu10.40

---------------
qemu (1:2.5+dfsg-5ubuntu10.40) xenial; urgency=medium

  * Restore patches that caused regression
    - d/p/lp1823458/add-VirtIONet-vhost_stopped-flag-to-prevent-multiple.patch
    - d/p/lp1823458/do-not-call-vhost_net_cleanup-on-running-net-from-ch.patch
  * Fix regression introduced by above patches (LP: #1829380)
    - d/p/lp1829380.patch

  [ Rafael David Tinoco ]
  * d/p/lp1828288/target-i386-Set-AMD-alias-bits-after-filtering-CPUID.patch
    - Fix issues with CPUID_EXT2_AMD_ALIASES allowing guests using
      cpu passthrough to boot. (LP: #1828288)

 -- Dan Streetman <email address hidden> Thu, 16 May 2019 14:29:56 -0400

Hello Dan, or anyone else affected,

Accepted qemu into mitaka-proposed. The package will build now and be available in the Ubuntu Cloud Archive in a few hours, and then in the -proposed repository.

Please help us by testing this new package. To enable the -proposed repository:

  sudo add-apt-repository cloud-archive:mitaka-proposed
  sudo apt-get update

Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-mitaka-needed to verification-mitaka-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-mitaka-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

The verification of the Stable Release Update for qemu has completed successfully and the package has now been released to -updates. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

This bug was fixed in the package qemu - 1:2.5+dfsg-5ubuntu10.40~cloud0
---------------

 qemu (1:2.5+dfsg-5ubuntu10.40~cloud0) trusty-mitaka; urgency=medium
 .
   * New update for the Ubuntu Cloud Archive.
 .
 qemu (1:2.5+dfsg-5ubuntu10.40) xenial; urgency=medium
 .
   * Restore patches that caused regression
     - d/p/lp1823458/add-VirtIONet-vhost_stopped-flag-to-prevent-multiple.patch
     - d/p/lp1823458/do-not-call-vhost_net_cleanup-on-running-net-from-ch.patch
   * Fix regression introduced by above patches (LP: #1829380)
     - d/p/lp1829380.patch
 .
   [ Rafael David Tinoco ]
   * d/p/lp1828288/target-i386-Set-AMD-alias-bits-after-filtering-CPUID.patch
     - Fix issues with CPUID_EXT2_AMD_ALIASES allowing guests using
       cpu passthrough to boot. (LP: #1828288)