BUG at /build/buildd/linux-2.6.38/mm/swapfile.c:255
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Medium
|
Unassigned | ||
Natty |
Fix Released
|
Medium
|
Stefan Bader | ||
Oneiric |
Fix Released
|
Medium
|
Stefan Bader |
Bug Description
SRU Justification:
Impact: An upstream change in 2.6.31 tried to simplify the conditions of having the lazy mmu mode in paravirt disabled. With that in mind several instances where the lazy mmu mode was disabled explicitly have been removed. However it was found that from k(un)map_atomic there is a chance to cause an oops.
Fix: The following patch has been sent upstream (currently it is only in the -mm tree and linux-next). It has been tested to fix the problem on 2.6.38. The specific symptom seen, seems to have come up since 2.6.37, however the lines of code that are re-introduced have been removed since 2.6.31.
Testcase: Trying to do forks under high load should trigger the issue (at least on 2.6.37+ kernels)
--
I'm filing this bug in response to threads at [1] and [2]. From those threads, we see reported that
* the instance becomes unavailable.
* the issue is reported to have to have been seen multiple different instance types
[TYPE: m2.xlarge, m1.large, t1.micro ( all types have hung ) ]
* at [2] there is BUG_ON output pointing at swap, but I would not have expected a user of an m2.xlarge to be using swap, so I personally suspect that that hang is different.
[1] http://
[2] https:/
ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: linux-image-
ProcVersionSign
Uname: Linux 2.6.38-8-virtual x86_64
AlsaDevices:
total 0
crw------- 1 root root 116, 1 2011-09-19 17:02 seq
crw------- 1 root root 116, 33 2011-09-19 17:02 timer
AplayDevices: Error: [Errno 2] No such file or directory
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory
CurrentDmesg: [ 16.930013] eth0: no IPv6 routers present
Date: Mon Sep 19 17:23:59 2011
Ec2AMI: ami-1aad5273
Ec2AMIManifest: (unknown)
Ec2Availability
Ec2InstanceType: t1.micro
Ec2Kernel: aki-427d952b
Ec2Ramdisk: unavailable
Lspci:
Lsusb: Error: command ['lsusb'] failed with exit code 1:
ProcEnviron:
PATH=(custom, user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcKernelCmdLine: root=LABEL=
ProcModules: acpiphp 24097 0 - Live 0x0000000000000000
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
Changed in linux (Ubuntu): | |
status: | Incomplete → Confirmed |
tags: | added: server-o-ro |
tags: | added: patch |
description: | updated |
Changed in linux (Ubuntu Natty): | |
assignee: | nobody → Stefan Bader (stefan-bader-canonical) |
importance: | Undecided → Medium |
status: | New → Fix Committed |
Changed in linux (Ubuntu Oneiric): | |
assignee: | nobody → Stefan Bader (stefan-bader-canonical) |
importance: | Undecided → Medium |
status: | New → Fix Committed |
tags: |
added: verification-done-oneiric removed: verification-needed-oneiric |
This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:
apport-collect 854050
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.