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Bug 454270 - SCHED_FIFO spec violation
Summary: SCHED_FIFO spec violation
Alias: None
Product: Red Hat Enterprise MRG
Classification: Red Hat
Component: realtime-kernel
Version: beta
Hardware: All
OS: All
Target Milestone: 1.0.3
: ---
Assignee: Peter Zijlstra
QA Contact:
Depends On:
TreeView+ depends on / blocked
Reported: 2008-07-07 12:08 UTC by IBM Bug Proxy
Modified: 2014-08-11 05:40 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2008-10-07 19:21:34 UTC
Target Upstream Version:

Attachments (Terms of Use)
[PATCH] Enqueue deprioritized RT tasks to head of prio array (deleted)
2008-07-07 12:08 UTC, IBM Bug Proxy
no flags Details

System ID Priority Status Summary Last Updated
IBM Linux Technology Center 46078 None None None Never
Red Hat Product Errata RHSA-2008:0857 normal SHIPPED_LIVE Important: kernel security and bug fix update 2008-10-07 19:18:59 UTC

Description IBM Bug Proxy 2008-07-07 12:08:21 UTC
=Comment: #0=================================================
Darren V. Hart <> - 2008-07-03 13:10 EDT
According to the SUS, when a SCHED_FIFO task's priority is lowered, it should be
added to the head of the corresponding priority array:

Peter Z. noticed this and wrote a patch to address it:

The dequeue_rt_stack() apparently still needs some work according to peterz

=Comment: #2=================================================
Darren V. Hart <> - 2008-07-03 13:22 EDT
The enqueue_task changed in 2.6.25, so a backport will be required.  It's a
simple patch, so that shouldn't pose a problem.

=Comment: #3=================================================
Darren V. Hart <> - 2008-07-03 15:01 EDT
I've backported the patch and have an R2 patch ready.  Currently under test on
elm3b172 running
=Comment: #4=================================================
Darren V. Hart <> - 2008-07-03 18:27 EDT

[PATCH] Enqueue deprioritized RT tasks to head of prio array

The attached patch is currently undergoing release-testing.

Comment 1 IBM Bug Proxy 2008-07-07 12:08:24 UTC
Created attachment 311140 [details]
[PATCH] Enqueue deprioritized RT tasks to head of prio array

Comment 2 Clark Williams 2008-08-20 13:46:33 UTC
Are we good with this one?

Comment 3 IBM Bug Proxy 2008-08-20 17:00:53 UTC
(In reply to comment #11)
> ------- Comment From 2008-08-20 09:46:33 EDT-------
> Are we good with this one?


Comment 5 David Sommerseth 2008-10-06 16:38:27 UTC
Verified by code review

Comment 7 errata-xmlrpc 2008-10-07 19:21:34 UTC
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.

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