| 2019-02-06 11:07:56 |
Ken Sharp |
bug |
|
|
added bug |
| 2019-02-06 11:07:56 |
Ken Sharp |
attachment added |
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dmesg.txt https://bugs.launchpad.net/bugs/1814874/+attachment/5236292/+files/dmesg.txt |
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| 2019-02-06 11:08:25 |
Ken Sharp |
bug watch added |
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https://bugzilla.kernel.org/show_bug.cgi?id=201603 |
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| 2019-02-06 11:08:25 |
Ken Sharp |
bug task added |
|
systemd |
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| 2019-02-06 11:08:34 |
Ken Sharp |
bug task deleted |
systemd |
|
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| 2019-02-06 11:09:12 |
Ken Sharp |
bug task added |
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linux |
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| 2019-02-06 12:39:18 |
Bug Watch Updater |
linux: status |
Unknown |
Confirmed |
|
| 2019-02-06 12:39:18 |
Bug Watch Updater |
linux: importance |
Unknown |
High |
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| 2019-02-06 12:39:23 |
Bug Watch Updater |
bug watch added |
|
https://bugzilla.kernel.org/show_bug.cgi?id=198585 |
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| 2019-03-04 17:03:44 |
Bug Watch Updater |
linux: status |
Confirmed |
Fix Released |
|
| 2019-03-04 17:38:05 |
Ken Sharp |
tags |
amd64 apport-bug bionic kernel-bug kernel-bug-exists-upstream |
amd64 apport-bug bionic kernel-bug kernel-fixed-upstream |
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| 2019-04-02 07:47:45 |
Po-Hsu Lin |
affects |
linux-signed-hwe (Ubuntu) |
linux (Ubuntu) |
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| 2019-04-09 09:41:11 |
Po-Hsu Lin |
bug |
|
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added subscriber Po-Hsu Lin |
| 2019-04-09 09:42:24 |
Po-Hsu Lin |
linux (Ubuntu): assignee |
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Po-Hsu Lin (cypressyew) |
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| 2019-04-09 09:42:26 |
Po-Hsu Lin |
linux (Ubuntu): status |
New |
In Progress |
|
| 2019-04-12 04:40:50 |
Po-Hsu Lin |
nominated for series |
|
Ubuntu Cosmic |
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| 2019-04-12 04:40:50 |
Po-Hsu Lin |
bug task added |
|
linux (Ubuntu Cosmic) |
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| 2019-04-12 11:10:51 |
Po-Hsu Lin |
nominated for series |
|
Ubuntu Bionic |
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| 2019-04-12 11:10:51 |
Po-Hsu Lin |
bug task added |
|
linux (Ubuntu Bionic) |
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| 2019-04-12 11:11:00 |
Po-Hsu Lin |
linux (Ubuntu Bionic): status |
New |
In Progress |
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| 2019-04-12 11:11:02 |
Po-Hsu Lin |
linux (Ubuntu Cosmic): status |
New |
In Progress |
|
| 2019-04-12 11:11:16 |
Po-Hsu Lin |
linux (Ubuntu): status |
In Progress |
Fix Released |
|
| 2019-04-12 11:11:22 |
Po-Hsu Lin |
tags |
amd64 apport-bug bionic kernel-bug kernel-fixed-upstream |
amd64 apport-bug bionic cosmic kernel-bug kernel-fixed-upstream |
|
| 2019-04-17 03:28:15 |
Po-Hsu Lin |
description |
Under memory pressure, my VM locks up. This has been reported upstream though I don't know how far any solution has progressed.
https://bugzilla.kernel.org/show_bug.cgi?id=201603
Feb 6 07:15:42 vps632258 kernel: [151336.450064] z3fold: unknown buddy id 0
Feb 6 07:15:42 vps632258 kernel: [151336.454450] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
The little bit of log I managed to salvage is attached.
This has happened to two identical VMs. Unusually it has not occurred on a third VM which is configured the same but has less RAM (fingers crossed it won't).
Irrelevant information:
I thought the lock-ups were due to me using a BTRFS filesystem, however I swapped over to NILFS2 and this still occurs. The only difference seems to be that I am now able to grab some of the kernel output.
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.18.0-14-generic 4.18.0-14.15~18.04.1
ProcVersionSignature: Ubuntu 4.18.0-14.15~18.04.1-generic 4.18.20
Uname: Linux 4.18.0-14-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
Date: Wed Feb 6 10:55:05 2019
ProcEnviron:
TERM=xterm
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_GB.UTF-8
SHELL=/bin/bash
SourcePackage: linux-signed-hwe
UpgradeStatus: No upgrade log present (probably fresh install) |
== Justification ==
When using z3fold and zswap on a VM under overcommitted memory stress,
z3fold will complains about an "unknown buddy id 0" and fail to get a
pointer to the mapped allocation in z3fold_map().
z3fold: unknown buddy id 0
WARNING: CPU: 2 PID: 1584 at mm/z3fold.c:971 z3fold_zpool_map+0xce/0x100 [z3fold]
And it will leads to a null pointer dereference in zswap
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 2 PID: 1584 Comm: stress Tainted: G W 4.18.0-17-generic #18-Ubuntu
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-1ubuntu1 04/01/2014
RIP: 0010:zswap_writeback_entry+0x4d/0x360
== Fix ==
ca0246bb (z3fold: fix possible reclaim races)
This patch has already in Disco, and can be cherry-picked into B/C.
Not needed for Xenial and older kernels as z3fold is not supported.
== Test ==
Test kernels for Bionic / Cosmic could be found here:
http://people.canonical.com/~phlin/kernel/lp-1814874-z3fold-zswap/Bionic/
http://people.canonical.com/~phlin/kernel/lp-1814874-z3fold-zswap/Cosmic/
This issue can be reproduced easily in a KVM with the following setup:
* 8G disk, 4G RAM, 4 CPUs
* 1G swap
* "zswap.enabled=1 zswap.zpool=z3fold zswap.max_pool_percent=7" added to grub
* "z3fold" module added into /etc/initramfs-tools/modules
Stress it with two childs running:
* stress --vm-bytes 512M --vm 4 --vm-hang 3
* stress --vm-bytes 512M --vm 4 --vm-hang 7
The VM is expected to crash within 5 minutes.
With the patched kernel, the VM can withstand this stress for over an
hour with crashing with this issue
== Regression potential ==
Small.
Fix limited to z3fold. User needs to enable it explicitly for this
feature.
== Original Bug Report ==
Under memory pressure, my VM locks up. This has been reported upstream though I don't know how far any solution has progressed.
https://bugzilla.kernel.org/show_bug.cgi?id=201603
Feb 6 07:15:42 vps632258 kernel: [151336.450064] z3fold: unknown buddy id 0
Feb 6 07:15:42 vps632258 kernel: [151336.454450] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
The little bit of log I managed to salvage is attached.
This has happened to two identical VMs. Unusually it has not occurred on a third VM which is configured the same but has less RAM (fingers crossed it won't).
Irrelevant information:
I thought the lock-ups were due to me using a BTRFS filesystem, however I swapped over to NILFS2 and this still occurs. The only difference seems to be that I am now able to grab some of the kernel output.
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.18.0-14-generic 4.18.0-14.15~18.04.1
ProcVersionSignature: Ubuntu 4.18.0-14.15~18.04.1-generic 4.18.20
Uname: Linux 4.18.0-14-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
Date: Wed Feb 6 10:55:05 2019
ProcEnviron:
TERM=xterm
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_GB.UTF-8
SHELL=/bin/bash
SourcePackage: linux-signed-hwe
UpgradeStatus: No upgrade log present (probably fresh install) |
|
| 2019-04-23 15:37:16 |
Kleber Sacilotto de Souza |
linux (Ubuntu Cosmic): status |
In Progress |
Fix Committed |
|
| 2019-04-23 15:37:18 |
Kleber Sacilotto de Souza |
linux (Ubuntu Bionic): status |
In Progress |
Fix Committed |
|
| 2019-04-25 22:32:29 |
Ubuntu Kernel Bot |
tags |
amd64 apport-bug bionic cosmic kernel-bug kernel-fixed-upstream |
amd64 apport-bug bionic cosmic kernel-bug kernel-fixed-upstream verification-needed-cosmic |
|
| 2019-04-29 16:04:02 |
Ubuntu Kernel Bot |
tags |
amd64 apport-bug bionic cosmic kernel-bug kernel-fixed-upstream verification-needed-cosmic |
amd64 apport-bug bionic cosmic kernel-bug kernel-fixed-upstream verification-needed-bionic verification-needed-cosmic |
|
| 2019-05-08 09:59:16 |
Po-Hsu Lin |
tags |
amd64 apport-bug bionic cosmic kernel-bug kernel-fixed-upstream verification-needed-bionic verification-needed-cosmic |
amd64 apport-bug bionic cosmic kernel-bug kernel-fixed-upstream verification-done-bionic verification-needed-cosmic |
|
| 2019-05-09 03:12:38 |
Po-Hsu Lin |
tags |
amd64 apport-bug bionic cosmic kernel-bug kernel-fixed-upstream verification-done-bionic verification-needed-cosmic |
amd64 apport-bug bionic cosmic kernel-bug kernel-fixed-upstream verification-done-bionic verification-done-cosmic |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
linux (Ubuntu Bionic): status |
Fix Committed |
Fix Released |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2017-5715 |
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| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
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2017-5753 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2017-5754 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2018-12126 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2018-12127 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2018-12130 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2018-16884 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2018-3620 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2018-3639 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2018-3646 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2019-3874 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2019-3882 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2019-9500 |
|
| 2019-05-14 19:00:51 |
Launchpad Janitor |
cve linked |
|
2019-9503 |
|
| 2019-05-14 19:04:10 |
Launchpad Janitor |
linux (Ubuntu Cosmic): status |
Fix Committed |
Fix Released |
|
| 2019-05-14 19:04:10 |
Launchpad Janitor |
cve linked |
|
2019-3887 |
|
