| 2017-10-27 17:55:36 |
Thadeu Lima de Souza Cascardo |
bug |
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added bug |
| 2017-10-27 17:55:46 |
Thadeu Lima de Souza Cascardo |
nominated for series |
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Ubuntu Artful |
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| 2017-10-27 17:55:54 |
Thadeu Lima de Souza Cascardo |
nominated for series |
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Ubuntu Bionic |
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| 2017-10-27 17:56:06 |
Thadeu Lima de Souza Cascardo |
bug task added |
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linux (Ubuntu) |
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| 2017-10-27 17:56:41 |
Thadeu Lima de Souza Cascardo |
bug |
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added subscriber Nish Aravamudan |
| 2017-10-27 18:00:07 |
Ubuntu Kernel Bot |
linux (Ubuntu): status |
New |
Incomplete |
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| 2017-10-27 18:23:20 |
Thadeu Lima de Souza Cascardo |
linux (Ubuntu): status |
Incomplete |
Triaged |
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| 2017-10-27 18:23:23 |
Thadeu Lima de Souza Cascardo |
makedumpfile (Ubuntu): status |
New |
Triaged |
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| 2017-10-27 18:23:32 |
Thadeu Lima de Souza Cascardo |
makedumpfile (Ubuntu): assignee |
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Thadeu Lima de Souza Cascardo (cascardo) |
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| 2017-11-07 18:59:27 |
Thadeu Lima de Souza Cascardo |
description |
The linux kernel won't boot when crashkernel parameter tells it to load a crash kernel at 32Mi on ppc64el on artful.
This happens because the artful kernel is too big. In fact, multiple requirements on the architecture lead to that:
Kernel memory at address 0 is reserved.
crashkernel must be at first RMO, so architecture puts it at 128Mi. However, kdump-tools currently puts it at @32Mi because of bug https://bugs.launchpad.net/ubuntu/+source/makedumpfile/+bug/1567539.
PACA and LPPACA need to be at the first RMO as well, and with 2048 CPUs, they take more than 5MB and 2MiB, respectively.
With the kernel now taking around 25MB from stext to _end, the kernel can't reserve enough memory for PACA or LPPACA right after boot, and it panics.
So, right after installing kdump-tools on artful, and rebooting, the kernel won't boot, with no sign of life as we haven't even started any console. Investigation for this issue took an entire day.
The fix would be setting the loading address to 128MiB, and start reducing size of PACA and maybe remove some of the requirements for the location of PACA and crash kernel.
I would not even set the loading address of the crash kernel in the parameter itself, and leave it to the kernel to decide it, which it already does and already would put it at 128Mi.
Cascardo. |
[Impact]
On Power Systems, the kernel won't boot when given a crashkernel parameter with an offset/start address of 32M. No output will be shown, giving no clue to the user why the system has not booted, or what the problem is.
[Test Case]
Installing kdump-tools on artful, then booting the system. It won't boot. With the fix, it boots and the crash kernel is reserved.
[Regression Potential]
Some Power Systems might have problems loading the kernel at this address. LP#1567539 is not really clear if PowerNV systems won't kdump when using an address different from 32M. However, it has been requested from an IBM person to test it with 128M instead, and no particular problem was shown. It's possible that there was no reason at first to use 32M, and no problems will be found on either PowerNV or other systems on the field. On the other hand, it's possible they might break kdump. But, right now, those systems won't even boot the first kernel without this change.
----
The linux kernel won't boot when crashkernel parameter tells it to load a crash kernel at 32Mi on ppc64el on artful.
This happens because the artful kernel is too big. In fact, multiple requirements on the architecture lead to that:
Kernel memory at address 0 is reserved.
crashkernel must be at first RMO, so architecture puts it at 128Mi. However, kdump-tools currently puts it at @32Mi because of bug https://bugs.launchpad.net/ubuntu/+source/makedumpfile/+bug/1567539.
PACA and LPPACA need to be at the first RMO as well, and with 2048 CPUs, they take more than 5MB and 2MiB, respectively.
With the kernel now taking around 25MB from stext to _end, the kernel can't reserve enough memory for PACA or LPPACA right after boot, and it panics.
So, right after installing kdump-tools on artful, and rebooting, the kernel won't boot, with no sign of life as we haven't even started any console. Investigation for this issue took an entire day.
The fix would be setting the loading address to 128MiB, and start reducing size of PACA and maybe remove some of the requirements for the location of PACA and crash kernel.
I would not even set the loading address of the crash kernel in the parameter itself, and leave it to the kernel to decide it, which it already does and already would put it at 128Mi.
Cascardo. |
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| 2017-11-07 18:59:49 |
Thadeu Lima de Souza Cascardo |
attachment added |
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makedumpfile_1.6.1-2ubuntu0.1.diff https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1728115/+attachment/5005511/+files/makedumpfile_1.6.1-2ubuntu0.1.diff |
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| 2017-11-07 19:00:03 |
Thadeu Lima de Souza Cascardo |
linux (Ubuntu): status |
Triaged |
In Progress |
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| 2017-11-07 19:00:07 |
Thadeu Lima de Souza Cascardo |
makedumpfile (Ubuntu): status |
Triaged |
In Progress |
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| 2017-11-07 19:00:19 |
Thadeu Lima de Souza Cascardo |
linux (Ubuntu): status |
In Progress |
New |
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| 2017-11-07 19:30:07 |
Ubuntu Kernel Bot |
linux (Ubuntu): status |
New |
Incomplete |
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| 2017-11-08 00:32:53 |
Ubuntu Foundations Team Bug Bot |
tags |
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patch |
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| 2017-11-08 00:33:04 |
Ubuntu Foundations Team Bug Bot |
bug |
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added subscriber Ubuntu Sponsors Team |
| 2017-11-21 13:21:17 |
Thadeu Lima de Souza Cascardo |
makedumpfile (Ubuntu): importance |
Undecided |
High |
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| 2017-11-21 14:03:59 |
Andy Whitcroft |
bug task added |
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linux (Ubuntu Artful) |
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| 2017-11-21 14:03:59 |
Andy Whitcroft |
bug task added |
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makedumpfile (Ubuntu Artful) |
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| 2017-11-21 14:04:05 |
Andy Whitcroft |
bug task added |
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linux (Ubuntu Bionic) |
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| 2017-11-21 14:04:05 |
Andy Whitcroft |
bug task added |
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makedumpfile (Ubuntu Bionic) |
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| 2017-11-21 14:13:58 |
Thadeu Lima de Souza Cascardo |
makedumpfile (Ubuntu Artful): status |
New |
In Progress |
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| 2017-11-21 14:14:02 |
Thadeu Lima de Souza Cascardo |
makedumpfile (Ubuntu Artful): importance |
Undecided |
High |
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| 2017-11-21 14:14:06 |
Thadeu Lima de Souza Cascardo |
makedumpfile (Ubuntu Artful): assignee |
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Thadeu Lima de Souza Cascardo (cascardo) |
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| 2017-12-05 12:09:14 |
Thadeu Lima de Souza Cascardo |
attachment added |
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fix for bionic https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1728115/+attachment/5018771/+files/makedumpfile_1.6.2-1ubuntu0.1.diff |
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| 2017-12-13 17:36:41 |
Launchpad Janitor |
makedumpfile (Ubuntu Bionic): status |
In Progress |
Fix Released |
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| 2017-12-14 21:05:29 |
Brian Murray |
makedumpfile (Ubuntu Artful): status |
In Progress |
Fix Committed |
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| 2017-12-14 21:05:32 |
Brian Murray |
bug |
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added subscriber Ubuntu Stable Release Updates Team |
| 2017-12-14 21:05:34 |
Brian Murray |
bug |
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added subscriber SRU Verification |
| 2017-12-14 21:05:38 |
Brian Murray |
tags |
patch |
patch verification-needed verification-needed-artful |
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| 2017-12-14 23:52:33 |
Brian Murray |
removed subscriber Ubuntu Sponsors Team |
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| 2018-03-21 06:40:10 |
bugproxy |
tags |
patch verification-needed verification-needed-artful |
architecture-ppc64le bugnameltc-165886 patch severity-medium targetmilestone-inin--- |
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| 2018-03-21 14:48:09 |
Thadeu Lima de Souza Cascardo |
tags |
architecture-ppc64le bugnameltc-165886 patch severity-medium targetmilestone-inin--- |
architecture-ppc64le bugnameltc-165886 patch severity-medium targetmilestone-inin--- verification-done verification-done-artful |
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| 2018-03-21 14:59:21 |
bugproxy |
tags |
architecture-ppc64le bugnameltc-165886 patch severity-medium targetmilestone-inin--- verification-done verification-done-artful |
architecture-ppc64le targetmilestone-inin--- |
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| 2018-03-21 15:12:46 |
Thadeu Lima de Souza Cascardo |
tags |
architecture-ppc64le targetmilestone-inin--- |
architecture-ppc64le targetmilestone-inin--- verification-done verification-done-artful |
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| 2018-03-21 21:20:25 |
bugproxy |
tags |
architecture-ppc64le targetmilestone-inin--- verification-done verification-done-artful |
architecture-ppc64le bugnameltc-165886 severity-medium targetmilestone-inin--- verification-done verification-done-artful |
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| 2018-03-26 09:06:27 |
Launchpad Janitor |
makedumpfile (Ubuntu Artful): status |
Fix Committed |
Fix Released |
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| 2018-03-26 09:06:36 |
Łukasz Zemczak |
removed subscriber Ubuntu Stable Release Updates Team |
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| 2018-06-13 11:19:35 |
bugproxy |
tags |
architecture-ppc64le bugnameltc-165886 severity-medium targetmilestone-inin--- verification-done verification-done-artful |
architecture-ppc64le bugnameltc-165886 severity-medium targetmilestone-inin1710 verification-done verification-done-artful |
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