Bug 104724 - top occasionally consumes 1 CPU
top occasionally consumes 1 CPU
Product: Red Hat Enterprise Linux 2.1
Classification: Red Hat
Component: procps (Show other bugs)
i386 Linux
medium Severity medium
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Assigned To: Tomas Smetana
Brian Brock
Depends On:
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Reported: 2003-09-19 16:04 EDT by aaron bos
Modified: 2007-11-30 17:06 EST (History)
1 user (show)

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Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 2007-10-19 15:24:05 EDT
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RHEL 7.3 requirements from Atomic Host:
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Description aaron bos 2003-09-19 16:04:40 EDT
From Bugzilla Helper:
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows 98)

Description of problem:
At random intervals, maybe once a month across 30 servers, I'm alerted to high 
CPU utilization on a server, and find a "top" command using 100% of a CPU.  
Typically the command has been running for several hours, and is running as a 
non-root user.

Version-Release number of selected component (if applicable):

How reproducible:
Couldn't Reproduce

Steps to Reproduce:
1.  Can't reproduce.  Happens randomly, infrequently.

Additional info:

Servers are Compaq DL360-G2s w/ 2 CPUs, 4 GB RAM.  Running 2.4.9-e.9smp.
Comment 1 Daniel Walsh 2004-02-11 08:43:16 EST
Can you reproduce this using 3.1.15 version?

Comment 2 Albert Cahalan 2004-07-20 13:33:19 EDT
It appears that sometimes the kernel will fail to sent SIGHUP
to the foreground process group when the session leader dies.
I've seen it after doing "su" in an xterm and then killing
the xterm. This is one way to cause the problem you're seeing.
Comment 3 Kurtis D. Rader 2005-02-21 17:20:33 EST
This also happens with procps-2.0.17-10 from RHEL AS 3 U3.

The primary problem is that top(1) doesn't terminate when a read of stding
returns an EOF indication. Specifically, after a "read(0, buf, 1)" returns
zero top(1) continues running. The secondary problem is that certain login
shells (such as the real ksh, not pdksh) don't propagate SIGHUP correctly.
Comment 4 RHEL Product and Program Management 2007-10-19 15:24:05 EDT
This bug is filed against RHEL2.1, which is in maintenance phase.
During the maintenance phase, only security errata and select mission
critical bug fixes will be released for enterprise products.  Since
this bug does not meet that criteria, it is now being closed.

For more information of the RHEL errata support policy, please visit:

If you feel this bug is indeed mission critical, please contact your
support representative.  You may be asked to provide detailed
information on how this bug is affecting you.

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