| 2022-05-24 09:29:19 |
bugproxy |
bug |
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added bug |
| 2022-05-24 09:29:21 |
bugproxy |
tags |
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architecture-s39064 bugnameltc-198360 severity-medium targetmilestone-inin--- |
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| 2022-05-24 09:29:22 |
bugproxy |
attachment added |
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patch that adds scheduling points https://bugs.launchpad.net/bugs/1975582/+attachment/5592577/+files/v2-0001-s390-gmap-voluntarily-schedule-during-key-setting.patch |
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| 2022-05-24 09:29:25 |
bugproxy |
attachment added |
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patch that uses cheaper key setting variant https://bugs.launchpad.net/bugs/1975582/+attachment/5592578/+files/v2-0002-s390-pgtable-use-non-quiescing-sske-for-KVM-switc.patch |
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| 2022-05-24 09:29:29 |
bugproxy |
ubuntu: assignee |
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Skipper Bug Screeners (skipper-screen-team) |
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| 2022-05-24 09:29:33 |
bugproxy |
affects |
ubuntu |
linux (Ubuntu) |
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| 2022-05-24 10:04:31 |
Frank Heimes |
bug task added |
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ubuntu-z-systems |
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| 2022-05-24 10:22:45 |
Frank Heimes |
ubuntu-z-systems: importance |
Undecided |
Medium |
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| 2022-05-24 10:22:47 |
Frank Heimes |
linux (Ubuntu): importance |
Undecided |
Medium |
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| 2022-05-24 10:23:04 |
Frank Heimes |
ubuntu-z-systems: assignee |
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Skipper Bug Screeners (skipper-screen-team) |
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| 2022-05-24 14:12:58 |
Frank Heimes |
linux (Ubuntu): status |
New |
In Progress |
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| 2022-05-24 14:13:01 |
Frank Heimes |
ubuntu-z-systems: status |
New |
In Progress |
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| 2022-06-10 12:58:17 |
Frank Heimes |
nominated for series |
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Ubuntu Impish |
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| 2022-06-10 12:58:17 |
Frank Heimes |
bug task added |
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linux (Ubuntu Impish) |
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| 2022-06-10 12:58:17 |
Frank Heimes |
nominated for series |
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Ubuntu Jammy |
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| 2022-06-10 12:58:17 |
Frank Heimes |
bug task added |
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linux (Ubuntu Jammy) |
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| 2022-06-10 12:58:17 |
Frank Heimes |
nominated for series |
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Ubuntu Focal |
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| 2022-06-10 12:58:17 |
Frank Heimes |
bug task added |
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linux (Ubuntu Focal) |
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| 2022-06-10 12:58:27 |
Frank Heimes |
linux (Ubuntu): status |
In Progress |
Invalid |
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| 2022-06-10 12:58:35 |
Frank Heimes |
linux (Ubuntu Focal): status |
New |
In Progress |
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| 2022-06-10 12:58:38 |
Frank Heimes |
linux (Ubuntu Impish): status |
New |
In Progress |
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| 2022-06-10 12:58:42 |
Frank Heimes |
linux (Ubuntu Jammy): status |
New |
In Progress |
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| 2022-06-10 12:59:18 |
Frank Heimes |
description |
---Problem Description---
There can be rcu stalls when running lots of large guests with storage keys:
[1377614.579833] rcu: INFO: rcu_sched self-detected stall on CPU
[1377614.579845] rcu: 18-....: (2099 ticks this GP) idle=54e/1/0x4000000000000002 softirq=35598716/35598716 fqs=998
[1377614.579895] (t=2100 jiffies g=155867385 q=20879)
[1377614.579898] Task dump for CPU 18:
[1377614.579899] CPU 1/KVM R running task 0 1030947 256019 0x06000004
[1377614.579902] Call Trace:
[1377614.579912] ([<0000001f1f4b4f52>] show_stack+0x7a/0xc0)
[1377614.579918] [<0000001f1ec8e96c>] sched_show_task.part.0+0xdc/0x100
[1377614.579919] [<0000001f1f4b7248>] rcu_dump_cpu_stacks+0xc0/0x100
[1377614.579924] [<0000001f1ecdd10c>] rcu_sched_clock_irq+0x75c/0x980
[1377614.579926] [<0000001f1eceb26c>] update_process_times+0x3c/0x80
[1377614.579931] [<0000001f1ecfcfea>] tick_sched_handle.isra.0+0x4a/0x70
[1377614.579932] [<0000001f1ecfd28e>] tick_sched_timer+0x5e/0xc0
[1377614.579933] [<0000001f1ecec294>] __hrtimer_run_queues+0x114/0x2f0
[1377614.579935] [<0000001f1ececfdc>] hrtimer_interrupt+0x12c/0x2a0
[1377614.579938] [<0000001f1ebecb6a>] do_IRQ+0xaa/0xb0
[1377614.579942] [<0000001f1f4c6d08>] ext_int_handler+0x130/0x134
[1377614.579945] [<0000001f1ec0af10>] ptep_zap_key+0x40/0x60
Contact Information = cborntra@de.ibm.com
---uname output---
RELEASE: 5.4.0-90-generic
VERSION: #101-Ubuntu SMP Fri Oct 15 19:59:45 UTC 2021
== Comment: #1 - Christian Borntraeger <cborntra@de.ibm.com> - 2022-05-24 03:59:37 ==
This is a test patch that might address the rcu stalls.
== Comment: #2 - Christian Borntraeger <cborntra@de.ibm.com> - 2022-05-24 04:00:22 ==
This is a 2nd patch that reduces the cost of key setting. |
SRU Justification:
==================
[Impact]
* Ubuntu on s390x KVM environments with lots of large guests with storage
keys can be affected by rcu stalls.
* These rcu stalls can cause the system to crash/dump.
[Fix]
* 3ae11dbcfac9 3ae11dbcfac906a8c3a480e98660a823130dc16a "s390/mm: use non-quiescing sske for KVM switch to keyed guest"
* 6d5946274df1 6d5946274df1fff539a7eece458a43be733d1db8 "s390/gmap: voluntarily schedule during key setting"
[Test Plan]
* There is no trigger or direct test or re-creation of the
problem situation possible, but...
* and IBM z13 or LinuxONE (or never) LPAR is needed that
runs Ubuntu Server 20.04 LTS or 18.04 LTS with HWE kernel
and acts as KVM host with again several large guests running
on top with storage groups.
* Let such a system running for days under significant load
and watch the logs for rcu issues.
* Prior to the submission of this SRU patched test kernels
for focal 5.4 and bionic hwe-5.4 were created and tested.
They ran for days at a staging environemnt at IBM
without further issues.
* The modifications are all limited to s390x.
* A test kernel was build (see below) that ran in a test environment
at IBM under appropriate load for several days.
[Where problems could occur]
* Due to the change for the KVM switch to keyed guest
from classic sske to non-quiescing sske
the KVM behaviour might have changed and the storage keys harmed.
* The now more generous scheduling while setting keys
has an impact on the guest memory management and mapping
which will lead to a different performance.
* This, with the introduction of __s390_enable_skey_pmd and
cond_resched, might increase the overhead in certain situations,
but eventually improves the responsiveness over time,
hence avoid rcu stalls.
[Other Info]
* Since the patches are upstream in 5.19-rc1,
they will be included in the kernel that is planned for kinetic (5.19).
* Hence this is an SRU to jammy, impish and focal.
__________
---Problem Description---
There can be rcu stalls when running lots of large guests with storage keys:
[1377614.579833] rcu: INFO: rcu_sched self-detected stall on CPU
[1377614.579845] rcu: 18-....: (2099 ticks this GP) idle=54e/1/0x4000000000000002 softirq=35598716/35598716 fqs=998
[1377614.579895] (t=2100 jiffies g=155867385 q=20879)
[1377614.579898] Task dump for CPU 18:
[1377614.579899] CPU 1/KVM R running task 0 1030947 256019 0x06000004
[1377614.579902] Call Trace:
[1377614.579912] ([<0000001f1f4b4f52>] show_stack+0x7a/0xc0)
[1377614.579918] [<0000001f1ec8e96c>] sched_show_task.part.0+0xdc/0x100
[1377614.579919] [<0000001f1f4b7248>] rcu_dump_cpu_stacks+0xc0/0x100
[1377614.579924] [<0000001f1ecdd10c>] rcu_sched_clock_irq+0x75c/0x980
[1377614.579926] [<0000001f1eceb26c>] update_process_times+0x3c/0x80
[1377614.579931] [<0000001f1ecfcfea>] tick_sched_handle.isra.0+0x4a/0x70
[1377614.579932] [<0000001f1ecfd28e>] tick_sched_timer+0x5e/0xc0
[1377614.579933] [<0000001f1ecec294>] __hrtimer_run_queues+0x114/0x2f0
[1377614.579935] [<0000001f1ececfdc>] hrtimer_interrupt+0x12c/0x2a0
[1377614.579938] [<0000001f1ebecb6a>] do_IRQ+0xaa/0xb0
[1377614.579942] [<0000001f1f4c6d08>] ext_int_handler+0x130/0x134
[1377614.579945] [<0000001f1ec0af10>] ptep_zap_key+0x40/0x60
Contact Information = cborntra@de.ibm.com
---uname output---
RELEASE: 5.4.0-90-generic
VERSION: #101-Ubuntu SMP Fri Oct 15 19:59:45 UTC 2021
== Comment: #1 - Christian Borntraeger <cborntra@de.ibm.com> - 2022-05-24 03:59:37 ==
This is a test patch that might address the rcu stalls.
== Comment: #2 - Christian Borntraeger <cborntra@de.ibm.com> - 2022-05-24 04:00:22 ==
This is a 2nd patch that reduces the cost of key setting. |
|
| 2022-06-10 12:59:23 |
Frank Heimes |
linux (Ubuntu Focal): importance |
Undecided |
Medium |
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| 2022-06-10 12:59:25 |
Frank Heimes |
linux (Ubuntu Impish): importance |
Undecided |
Medium |
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| 2022-06-10 12:59:28 |
Frank Heimes |
linux (Ubuntu Jammy): importance |
Undecided |
Medium |
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| 2022-06-10 12:59:41 |
Frank Heimes |
linux (Ubuntu Focal): assignee |
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Canonical Kernel Team (canonical-kernel-team) |
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| 2022-06-10 12:59:47 |
Frank Heimes |
linux (Ubuntu Impish): assignee |
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Canonical Kernel Team (canonical-kernel-team) |
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| 2022-06-10 12:59:53 |
Frank Heimes |
linux (Ubuntu Jammy): assignee |
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Canonical Kernel Team (canonical-kernel-team) |
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| 2022-06-21 17:23:55 |
Stefan Bader |
linux (Ubuntu Jammy): status |
In Progress |
Fix Committed |
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| 2022-06-21 17:23:58 |
Stefan Bader |
linux (Ubuntu Impish): status |
In Progress |
Fix Committed |
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| 2022-06-21 17:24:01 |
Stefan Bader |
linux (Ubuntu Focal): status |
In Progress |
Fix Committed |
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| 2022-06-21 18:18:27 |
Frank Heimes |
ubuntu-z-systems: status |
In Progress |
Fix Committed |
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| 2022-06-29 01:40:34 |
Ubuntu Kernel Bot |
tags |
architecture-s39064 bugnameltc-198360 severity-medium targetmilestone-inin--- |
architecture-s39064 bugnameltc-198360 severity-medium targetmilestone-inin--- verification-needed-jammy |
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| 2022-06-29 01:43:26 |
Ubuntu Kernel Bot |
tags |
architecture-s39064 bugnameltc-198360 severity-medium targetmilestone-inin--- verification-needed-jammy |
architecture-s39064 bugnameltc-198360 severity-medium targetmilestone-inin--- verification-needed-focal verification-needed-jammy |
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| 2022-06-29 08:49:55 |
bugproxy |
tags |
architecture-s39064 bugnameltc-198360 severity-medium targetmilestone-inin--- verification-needed-focal verification-needed-jammy |
architecture-s39064 bugnameltc-198360 severity-medium targetmilestone-inin2004 verification-needed-focal verification-needed-jammy |
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| 2022-06-29 10:39:50 |
bugproxy |
tags |
architecture-s39064 bugnameltc-198360 severity-medium targetmilestone-inin2004 verification-needed-focal verification-needed-jammy |
architecture-s39064 bugnameltc-198360 severity-medium targetmilestone-inin2004 verification-done-focal verification-done-jammy |
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| 2022-07-11 13:18:21 |
Launchpad Janitor |
linux (Ubuntu Focal): status |
Fix Committed |
Fix Released |
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| 2022-07-11 13:18:21 |
Launchpad Janitor |
cve linked |
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2022-1789 |
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| 2022-07-11 13:20:28 |
Launchpad Janitor |
linux (Ubuntu Jammy): status |
Fix Committed |
Fix Released |
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| 2022-07-11 14:37:38 |
Frank Heimes |
linux (Ubuntu Impish): status |
Fix Committed |
Won't Fix |
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| 2022-07-11 14:37:42 |
Frank Heimes |
ubuntu-z-systems: status |
Fix Committed |
Fix Released |
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