L1T fix reading array beyond bounds

[cecilecaillol]

PR description:

Addressing issue #37696 where an array was read beyond bounds

[cecilecaillol]

@skinnari @tomalin This is an ad-hoc fix to reading indices beyond an array size. You may want to check the rest of the code to understand why this call happened. There are more details in the issue quoted in the description of the PR. If you are fine with this fix we can also merge it without further checks.

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-37700/29525

• This PR adds an extra 20KB to repository

[cmsbuild]

A new Pull Request was created by @cecilecaillol for master.

It involves the following packages:

• L1Trigger/TrackFindingTMTT (l1)

@epalencia, @cmsbuild, @cecilecaillol, @rekovic can you please review it and eventually sign? Thanks.
@Martin-Grunewald, @erikbutz, @skinnari, @missirol this is something you requested to watch as well.
@perrotta, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

[cecilecaillol]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-e1285c/24301/summary.html
COMMIT: 76382e9
CMSSW: CMSSW_12_4_X_2022-04-27-2300/slc7_amd64_gcc10
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/37700/24301/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 4 differences found in the comparisons
• DQMHistoTests: Total files compared: 49
• DQMHistoTests: Total histograms compared: 3695434
• DQMHistoTests: Total failures: 8
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3695404
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 48 files compared)
• Checked 205 log files, 45 edm output root files, 49 DQM output files
• TriggerResults: no differences found

[cecilecaillol]

@skinnari @tomalin kind reminder

[perrotta]

In

cmssw/L1Trigger/TrackFindingTMTT/src/KFbase.cc

Lines 241 to 244 in 76382e9

	while (kfDeadLayers.find(layer) != kfDeadLayers.end() && layerStubs[layer].empty()) {
	layer += 1;
	++nSkippedDeadLayers;
	}

if the 7th layer is the dead one, then layer gets increased to 8 and in the following kalmanAmbiguousLayer(etaReg, layer) the out-of-bound argument 8 is feed in input.

I think that the correct fix to the issue at hand should consider how to deal with such a case.

Analogously, also if the 7th layer is "kalmanAmbiguous" then layer becomes 8 afterwards, and probably also that case needs a special treatment in the code.

[skinnari]

I don’t know this part of the code well. @tomalin or @Jingyan95 or @tschuh should be able to comment better.

[tomalin]

I agree that the fix you propose makes sense.

[tomalin]

I agree that the fix you propose makes sense.

[cecilecaillol]

+l1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @perrotta, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[perrotta]

+1