| 2021-02-27 13:24:10 |
Bambang Pranoto |
bug |
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added bug |
| 2021-02-27 14:20:13 |
Hans-Christian |
bug |
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added subscriber Hans-Christian |
| 2021-02-27 14:20:22 |
Launchpad Janitor |
ubuntu: status |
New |
Confirmed |
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| 2021-02-27 14:21:38 |
Hans-Christian |
bug task added |
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dosemu (Ubuntu) |
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| 2021-02-27 14:47:33 |
Hans-Christian |
bug task deleted |
dosemu (Ubuntu) |
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| 2021-02-27 16:28:03 |
Ubuntu Foundations Team Bug Bot |
tags |
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bot-comment |
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| 2021-02-27 17:17:49 |
stsp |
bug |
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added subscriber stsp |
| 2021-02-27 17:28:12 |
stsp |
affects |
ubuntu |
linux (Ubuntu) |
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| 2021-02-27 17:30:05 |
stsp |
bug watch added |
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https://github.com/dosemu2/dosemu2/issues/1404 |
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| 2021-02-27 17:30:05 |
stsp |
bug task added |
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linux |
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| 2021-02-27 17:30:52 |
stsp |
affects |
linux |
dosemu2 |
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| 2021-02-27 23:24:34 |
Bug Watch Updater |
dosemu2: status |
Unknown |
New |
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| 2021-03-02 18:36:51 |
Guilherme G. Piccoli |
linux (Ubuntu): status |
Confirmed |
In Progress |
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| 2021-03-03 00:55:34 |
Bug Watch Updater |
dosemu2: status |
New |
Fix Released |
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| 2021-03-03 21:22:37 |
Guilherme G. Piccoli |
summary |
kernel 4.15.0-136 causes dosemu2 with kvm freezes |
Bionic kernel 4.15.0-136 causes dosemu2 (with kvm mode) freezes due to lack of KVM patch |
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| 2021-03-03 21:26:22 |
Guilherme G. Piccoli |
description |
With the latest kernel 4.15.0-136 updates on ubuntu 18.04 and ubuntu 16.04, dosemu2 with kvm freezes boot.
dosemu2 source: https://github.com/dosemu2/dosemu2
dosemu2 package can be obtained from https://launchpad.net/~dosemu2/+archive/ubuntu/ppa
1. ubuntu version
lsb_release -rd
Description: Ubuntu 18.04.5 LTS
Release: 18.04
2. package version
$ apt-cache policy dosemu2
dosemu2:
Installed: (none)
Candidate: (none)
Version table:
2.0~pre8-2 -1
100 /var/lib/dpkg/status
3. What is expected to happen: The dosemu program runs fine as in previous kernel version
4. What happened instead: The dosemu freezes on loading
I have also reported this problem to dosemu2 developer, here is my bug report:
https://github.com/dosemu2/dosemu2/issues/1404 |
[Impact]
* Since kernel 4.15.0-136, Bionic kernel included a very complex KVM fix for a kind of "race" in interrupt window with irqchip-split (reported in [0]). The fix was proposed in the form of a patch series containing 2 patches [1] - this was merged in Ubuntu though the stable tree, in the form of the following commit:
71cc849b7093 ("KVM: x86: Fix split-irqchip vs interrupt injection window request") [2]
* The problem is that such commit has a companion required commit, which was not proposed in the stable tree. In fact, there was a confusion among KVM community and the stable maintainer [3], due to the lack of such missing commit - because of that, the series was removed from stable trees 4.14.y and 4.9.y, but the solo commit was merged alone in Ubuntu kernel.
* Without the companion patch, we might have a KVM infinite "loop" condition in the core IRQ handling, since the merged commit requires an extra check in kvm_cpu_has_extint() and a condition "inversion" in kvm_cpu_get_extint(), only present in the missing companion patch. Users reported that this manifested as dosemu2 (running in KVM mode) to be stuck in kernel 4.15.0-136 and -137, while works fine in 4.15.0-135 and the
-137 plus the companion patch.
* So, we hereby backport the companion commit, originally upstream patch: 72c3bcdcda ("KVM: x86: handle !lapic_in_kernel case in kvm_cpu_*_extint") [4]
[Test Case]
* The test case proposed was the reported bug: try running dosemu2 (with kvm mode enabled) and it fails without the companion commit.
* In order to test the correctness of both fixes together, we could rely in the test proposed in [0] (running a guest with "noapic"), but it wasn't consistent and the VMM wasn't mentioned, so we might have a workaround mechanism in qemu, for example, preventing such test to reproduce the issue.
[Where problems could occur]
* Since this is a KVM core modification, it could affect interrupt handling in KVM but without the fix, we are already experiencing a bug. Also, both commits were backported to 5.4.y and 4.19.y, so Focal and subsequent released are already running with them.
[0] https://lore.kernel.org/kvm/62918f65ec78f8990278a6a0db0567968fa23e49.camel@infradead.org/
[1] https://lore.kernel.org/kvm/20201127112114.3219360-1-pbonzini@redhat.com/
[2] http://git.kernel.org/linus/71cc849b70
[3] https://lore.kernel.org/stable/d29c4b25-33f6-8d99-7a45-8f4e06f5ade6@redhat.com/
[4] http://git.kernel.org/linus/72c3bcdcda
<Original description>
With the latest kernel 4.15.0-136 updates on ubuntu 18.04 and ubuntu 16.04, dosemu2 with kvm freezes boot.
dosemu2 source: https://github.com/dosemu2/dosemu2
dosemu2 package can be obtained from https://launchpad.net/~dosemu2/+archive/ubuntu/ppa
1. ubuntu version
lsb_release -rd
Description: Ubuntu 18.04.5 LTS
Release: 18.04
2. package version
$ apt-cache policy dosemu2
dosemu2:
Installed: (none)
Candidate: (none)
Version table:
2.0~pre8-2 -1
100 /var/lib/dpkg/status
3. What is expected to happen: The dosemu program runs fine as in previous kernel version
4. What happened instead: The dosemu freezes on loading
I have also reported this problem to dosemu2 developer, here is my bug report:
https://github.com/dosemu2/dosemu2/issues/1404 |
|
| 2021-03-03 21:26:26 |
Guilherme G. Piccoli |
linux (Ubuntu): importance |
Undecided |
High |
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| 2021-03-03 21:26:28 |
Guilherme G. Piccoli |
linux (Ubuntu): assignee |
|
Guilherme G. Piccoli (gpiccoli) |
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| 2021-03-04 01:43:54 |
Bug Watch Updater |
dosemu2: status |
Fix Released |
New |
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| 2021-03-04 09:36:30 |
Stefan Bader |
nominated for series |
|
Ubuntu Bionic |
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| 2021-03-04 09:36:30 |
Stefan Bader |
bug task added |
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linux (Ubuntu Bionic) |
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| 2021-03-04 09:38:27 |
Stefan Bader |
linux (Ubuntu Bionic): importance |
Undecided |
High |
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| 2021-03-04 09:38:27 |
Stefan Bader |
linux (Ubuntu Bionic): status |
New |
In Progress |
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| 2021-03-04 09:38:27 |
Stefan Bader |
linux (Ubuntu Bionic): assignee |
|
Guilherme G. Piccoli (gpiccoli) |
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| 2021-03-04 09:38:48 |
Stefan Bader |
linux (Ubuntu): importance |
High |
Undecided |
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| 2021-03-04 09:38:48 |
Stefan Bader |
linux (Ubuntu): status |
In Progress |
Invalid |
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| 2021-03-04 09:38:48 |
Stefan Bader |
linux (Ubuntu): assignee |
Guilherme G. Piccoli (gpiccoli) |
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| 2021-03-05 09:36:24 |
Stefan Bader |
linux (Ubuntu Bionic): status |
In Progress |
Fix Committed |
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| 2021-03-15 21:45:51 |
Guilherme G. Piccoli |
bug |
|
|
added subscriber Guilherme G. Piccoli |
| 2021-03-25 15:23:42 |
Ubuntu Kernel Bot |
tags |
bot-comment |
bot-comment verification-needed-bionic |
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| 2021-03-26 04:34:31 |
Bambang Pranoto |
tags |
bot-comment verification-needed-bionic |
verification-done-bionic |
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| 2021-04-12 15:17:02 |
Launchpad Janitor |
linux (Ubuntu Bionic): status |
Fix Committed |
Fix Released |
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| 2021-04-12 15:17:02 |
Launchpad Janitor |
cve linked |
|
2018-13095 |
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| 2021-04-12 15:17:02 |
Launchpad Janitor |
cve linked |
|
2021-3348 |
|
| 2021-04-25 18:02:31 |
Bug Watch Updater |
dosemu2: status |
New |
Fix Released |
|
