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Fix of a hang in ITSClusterTask - #2680

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sawenzel merged 1 commit into
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sawenzel:fix-itsclustertask-dcolmap-oob-delete
Aug 18, 2026
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Fix of a hang in ITSClusterTask#2680
sawenzel merged 1 commit into
AliceO2Group:masterfrom
sawenzel:fix-itsclustertask-dcolmap-oob-delete

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This commit fixes a hang observed in the MC nightlies since 11. August 2026.

The patch corrects upon findings of a debug session which surfaced that

  • ITSTracksClustersQC never returns.
  • It keeps its semaphore, so the other timeframes never run.
  • The QC finalisation stalls and the GRID watchdog kills the job.
  • The task aborts inside free() while it is destroyed.
  • The crash handler then deadlocks, so the process never exits.

The destructor deletes the dcol maps in the inner barrel branch. For layers 0 to 2 this frees hDcolMapOBSor and hDcolMapOBEor at index -3, -2 and -1. They belong in the outer barrel branch.

startOfCycle resets the same histograms without a null check. createAllHistos skips disabled layers, so they can be null.

This commit fixes a hang observed in the MC nightlies since 11. August 2026.

The patch corrects upon findings of a debug session which surfaced that

- ITSTracksClustersQC never returns.
- It keeps its semaphore, so the other timeframes never run.
- The QC finalisation stalls and the GRID watchdog kills the job.
- The task aborts inside free() while it is destroyed.
- The crash handler then deadlocks, so the process never exits.

The destructor deletes the dcol maps in the inner barrel branch. For layers 0 to 2
this frees hDcolMapOBSor and hDcolMapOBEor at index -3, -2 and -1. They belong in
the outer barrel branch.

startOfCycle resets the same histograms without a null check. createAllHistos skips
disabled layers, so they can be null.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
@knopers8
knopers8 enabled auto-merge (squash) August 17, 2026 12:04
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thank you!

@sawenzel
sawenzel disabled auto-merge August 18, 2026 11:32
@sawenzel
sawenzel merged commit 7643a6e into AliceO2Group:master Aug 18, 2026
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@sawenzel

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@knopers8 : Could you please prepare a new tag for alidist?

@sawenzel
sawenzel deleted the fix-itsclustertask-dcolmap-oob-delete branch August 18, 2026 11:33
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3 participants