Prior to this update, running the hwclock --systohc command could halt a running system. This was due to the interrupt transactions being looped back from a local IOH (Input/Output Hub), through the IOH to a local CPU (erroneously), which caused a conflict with I/O port operations and other transactions. With this update, the conflicts are avoided and the system continues to run after executing the hwclock --systohc command.
Created attachment 464378[details]
Tested patch
Description of problem:
Problem originally noticed when
'hwclock --systohc' halted a running system.
Version-Release number of selected component (if applicable):
kernel-2.6.32-71
How reproducible:
Easily, but not 100%.
Steps to Reproduce:
1. boot system on UV hardware
2. hwclock --systohc ## ususally sufficient
3. hwclock
On one system also had to do the following before running it:
echo 4 >/proc/irq/8/smp_affinity
then run hwclock.
Actual results:
System halts with CATERR.
Expected results:
System continues to run.
Additional info:
The attached patch has been tested inside SGI on multiple systems.
PV# 1012363
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New Contents:
Prior to this update, running the hwclock --systohc command could halt a running system. This was due to the interrupt transactions being looped back from a local IOH (Input/Output Hub), through the IOH to a local CPU (erroneously), which caused a conflict with I/O port operations and other transactions. With this update, the conflicts are avoided and the system continues to run after executing the hwclock --systohc command.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.
http://rhn.redhat.com/errata/RHSA-2011-0542.html
Created attachment 464378 [details] Tested patch Description of problem: Problem originally noticed when 'hwclock --systohc' halted a running system. Version-Release number of selected component (if applicable): kernel-2.6.32-71 How reproducible: Easily, but not 100%. Steps to Reproduce: 1. boot system on UV hardware 2. hwclock --systohc ## ususally sufficient 3. hwclock On one system also had to do the following before running it: echo 4 >/proc/irq/8/smp_affinity then run hwclock. Actual results: System halts with CATERR. Expected results: System continues to run. Additional info: The attached patch has been tested inside SGI on multiple systems. PV# 1012363