Bug 446060 - kernel: sched_fair.c simplify sched_slice()
kernel: sched_fair.c simplify sched_slice()
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
All Linux
low Severity low
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Assigned To: Red Hat Product Security
: Security
Depends On: 447501
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Reported: 2008-05-12 10:12 EDT by Jan Lieskovsky
Modified: 2010-12-22 11:36 EST (History)
4 users (show)

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Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 2010-12-22 11:36:52 EST
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RHEL 7.3 requirements from Atomic Host:
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Description Jan Lieskovsky 2008-05-12 10:12:46 EDT
Description of problem:

The problem is in sched_slice() called by sys_sched_rr_get_interval():
time_slice = NS_TO_JIFFIES(sched_slice(cfs_rq_of(se), se));
sched_slice() will use 'cfs_rq->load.weight' as the base for a
division, which is zero for process 1.

Version-Release number of selected component (if applicable):
Linux kernel 2.6.24 up to

Additional info:

This issue not present on RHEL kernels (sched_slice first appeared
in 2.6.24). Filling only against the Fedora kernels.

The problem itself was fixed by Ingo with this commit (I think):
by using a different function on March 15. (2.6.25 rc phase sometime)

The code was changed back (and so broken again) to a version of the old version
6 weeks later by Peter in
and fixed afterwards in:
on a April 19 merge by Linus. (2.6.26 merge window)

Proposed upstream patch:

Comment 7 Vincent Danen 2010-12-22 11:36:52 EST
This was addressed via:

MRG: http://rhn.redhat.com/errata/RHSA-2008-0585.html

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