Ubuntu
linux-ec2 package

Kernel divide by zero panic in sched.c:update_sd_lb_stats

Bug #669096 reported by Brandon Black on 2010-10-31

This bug affects 1 person

Affects		Status	Importance	Assigned to	Milestone
	linux-ec2 (Ubuntu)	New	Undecided	Unassigned

Bug Description

host was an m2.2xlarge instance in us-east-1 (with EBS root and data volumes) running stock lucid and serving primarily as a MySQL server.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: linux-image-2.6.32-308-ec2 2.6.32-308.16
ProcVersionSignature: Ubuntu 2.6.32-308.16-ec2 2.6.32.15+drm33.5
Uname: Linux 2.6.32-308-ec2 x86_64
Architecture: amd64
Date: Sun Oct 31 09:58:32 2010
ProcEnviron:
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: linux-ec2

Tags:

Revision history for this message

Brandon Black (blblack) wrote on 2010-10-31:

crash output from ec2-get-console-output Edit (8.3 KiB, text/plain)
Dependencies.txt Edit (1.3 KiB, text/plain; charset="utf-8")

Revision history for this message

Brandon Black (blblack) wrote on 2010-10-31:

The part we crashed in is the code that calculates cpu scheduler stats, with a divide by zero. I've done some searching around on git.kernel.org and lxr.linux.no, and I don't see where any similar existing problem has been caught and fixed yet upstream through 2.6.32, but it could be non-obvious. Looking at linux_2.6.32-25.45.diff.gz from the relevant apt source for -virtual, I see a lot of patches to sched.c, some of which introduce new division operations. It wouldn't surprise me if the bug was in there somewhere.

Revision history for this message

Brandon Black (blblack) wrote on 2011-01-06:

This looks very likely to be related upstream: https://bugzilla.kernel.org/show_bug.cgi?id=16991

Revision history for this message

Brandon Black (blblack) wrote on 2011-01-06:

Ah, and from there I see a link to a different LP bug which has more details as well, should probably close this as a dupe of that one: https://bugs.launchpad.net/ubuntu/+source/linux-ec2/+bug/614853