Fix for handling of extremely rare case of CFEB data corruption

[barvic]

The CSC Unpacker side fix for handling of rare case CFEB data corruption, which could cause assertion failure in CSC Segment RECO module.

Original issue is described at https://hypernews.cern.ch/HyperNews/CMS/get/recoDevelopment/1391.html
Assertion failure is triggered, when number of expected time bins in CFEB data is not equal to 8.

[cmsbuild]

A new Pull Request was created by @barvic for CMSSW_7_4_X.

Fix for handling of extremely rare case of CFEB data corruption

It involves the following packages:

EventFilter/CSCRawToDigi

@cmsbuild, @cvuosalo, @slava77 can you please review it and eventually sign? Thanks.
@Martin-Grunewald this is something you requested to watch as well.
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@Degano you are the release manager for this.
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[slava77]

@cmsbuild please test

[slava77]

@barvic
I expect equivalent 75X and 76X PRs from you soon.
Thank you.

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/8920/console

[cmsbuild]

+1
Tested at: 9cadc86
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-11821/8920/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-11821/8920/summary.html

[cvuosalo]

+1

For #11821 9cadc86
Bug fix for an assertion failure and termination in the CSC unpacker. There should be no change in monitored quantities. #11824 and #11825 are the 75X and 76X versions of this PR.

The fix is satisfactory, and Jenkins tests against baseline CMSSW_7_4_X_2015-10-15-1100 show no significant differences, as expected. However, the Jenkins comparisons are incomplete. #11824 has complete Jenkins comparisons, and they also show no significant differences.
The bug was reproduced in CMSSW_7_4_14, and the bug fix was confirmed.

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_4_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_7_6_X is complete. This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @Degano, @smuzaffar

[slava77]

@davidlange6
please comment if this will go into 74X.
Technically, a patch release would be useful to avoid the crash if it happens again.

[davidlange6]

+1