https://bugs.kde.org/show_bug.cgi?id=492388
Bug ID: 492388
Summary: Detected nondeterminism in Valgrind's log for Helgrind
Classification: Developer tools
Product: valgrind
Version: 3.18.1
Platform: Ubuntu
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: helgrind
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Created attachment 173112
--> https://bugs.kde.org/attachment.cgi?id=173112&action=edit
PDF that shows file differences between Run #1 and Run #2 of the same binary
under Helgrind
Hi Valgrind Maintainers and Team!
I have been using Valgrind as a tool to check for nondeterministic behaviors
and I know that there are multiple subtools that Valgrind's suite comes with. I
would like to inquire about the Helgrind subtool in analyzing some of the
reports generated after each run against a binary. This nondeterminism concerns
the the Valgrind generated report. Out of 41 repositories we've tested against
Helgrind, we observed 4/41 showing nondeterministic reporting for their
respective binaries tested.
Would the respective team and its maintainers for this product take a look at
this issue and provide possible explanations? Thank you very much!
STEPS TO REPRODUCE
1. Use a GitHub Actions runner with Ubuntu 22.04 + Valgrind 3.18.1 pulled from
the Ubuntu package manager
2. Run your executable with Helgrind enabled.
3. Obtain the Valgrind report
OBSERVED RESULT
We noticed that out of these four repositories that reported nondeterminism in
their Valgrind logs, we saw two distinct variations these logs experienced:
either the difference in the number of errors reported and what errors are
reported or the different stack traces produced. In the given attachment, the
left column represents Run #1 while the right column represents Run #2. If you
analyze pages five and six of the attached PDF, you'll notice how Run #2
reports two additional possible data races. Additionally, both runs have
different error summary fields with the different error count and context
count.
ADDITIONAL INFORMATION
Scroll down to pages five and six of the attached PDF to see the difference
between the two runs of the same binary done under the same configurations.
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