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Bug 1773792 - Code in systopology can miss when cpu0 is offline
Summary: Code in systopology can miss when cpu0 is offline
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: rteval
Version: 8.2
Hardware: Unspecified
OS: Unspecified
unspecified
low
Target Milestone: rc
: 8.2
Assignee: John Kacur
QA Contact: Mike Stowell
URL:
Whiteboard:
Depends On:
Blocks: 1722609
TreeView+ depends on / blocked
 
Reported: 2019-11-18 22:37 UTC by John Kacur
Modified: 2020-04-28 15:29 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2020-04-28 15:29:01 UTC
Type: Bug
Target Upstream Version:
Embargoed:
pm-rhel: mirror+

Attachments (Terms of Use)
don't assume cpu0 cannot be offlined (1.10 KB, patch)
2019-11-19 11:41 UTC, John Kacur 		no flags Details | Diff
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Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2020:1571 0 None None None 2020-04-28 15:29:18 UTC

Description John Kacur 2019-11-18 22:37:45 UTC 
Description of problem:
covscan undcovered some deadcode. On some machines it is not possible for cpu0 to go offline, but if it is then the file /sys/devices/system/cpu/cpu0/online exists. Instead of just assuming that cpu0 cannot be offlined we need to properly test that.

Version-Release number of selected component (if applicable):
rteval-3.0-2.el8

How reproducible:
it can be rather difficult to reproduce, since it needs numa hardware where cpu0 can be offlined, and then you need to offline it.

I think for testing purposes it is sufficient that the covscan doesn't report this as deadcode, and then verify it by inspection
Comment 1 John Kacur 2019-11-18 22:44:15 UTC 
1. rteval-3.0/rteval/systopology.py:124: between: At condition "!os.path.exists(path + "/online") && (n == 0)", the value of "!os.path.exists(path + "/online") && (n == 0)" must be between 0 and 1.
2. rteval-3.0/rteval/systopology.py:120: cond_cannot_single: Condition "n == 0", taking false branch. Now the value of "n" cannot be equal to 0.
3. rteval-3.0/rteval/systopology.py:124: cannot_single: At condition "!os.path.exists(path + "/online") && (n == 0)", the value of "n" cannot be equal to 0.
4. rteval-3.0/rteval/systopology.py:124: truth: At condition "!os.path.exists(path + "/online") && (n == 0)", the truth value of "!os.path.exists(path + "/online") && (n == 0)" must be false.
5. rteval-3.0/rteval/systopology.py:124: possible_types: At condition "!os.path.exists(path + "/online") && (n == 0)", the type of "!os.path.exists(path + "/online") && (n == 0)" must be Boolean.
6. rteval-3.0/rteval/systopology.py:124: dead_error_condition: The condition "!os.path.exists(path + "/online") && (n == 0)" cannot be true.
7. rteval-3.0/rteval/systopology.py:125: dead_error_line: Execution cannot reach this statement: "return True;".
#   123|           # Some hardware doesn't allow cpu0 to be turned off
#   124|           if not os.path.exists(path + '/online') and n == 0:
#   125|->             return True
#   126|           else:
#   127|               return sysread(path, "online") == "1"
Comment 2 John Kacur 2019-11-19 11:41:21 UTC 
Created attachment 1637616 [details]
don't assume cpu0 cannot be offlined
Comment 8 errata-xmlrpc 2020-04-28 15:29:01 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:1571
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