Hi Felix, There was indeed a bug in how CTF trace index is parsed in Trace Compass. I created a fix in https://github.com/eclipse-tracecompass/org.eclipse.tracecompass/pull/427 If you find another issue in Trace Compass, you can file a bug here instead: https://github.com/eclipse-tracecompass/org.eclipse.tracecompass/issues Thank you, Arnaud Fiorini ________________________________ From: MOESSBAUER, Felix via lttng-dev Sent: Wednesday, August 5, 2026 6:16 AM To: MOESSBAUER, Felix via lttng-dev Subject: babeltrace master: trace-compass is unable to open trace with index Hi, the babeltrace version from the master branch (65fb4669f) is able to create LTTng index files. However, these index files seem to be incompatible with trace-compass. On loading such a trace, trace-compass (incubator version, 0.18.0- 20260711-0558, or release 12.0.0) issues the following error message: > Error initializing trace. > org.eclipse.tracecompass.tmf.core.exceptions.TmfTraceException: > Failed to allocate mapped byte buffer at 36 of size 416 on a > file of size 176 I double checked the traces with babeltrace and https://github.com/eepp/jacquesctf , which are both able to properly read the traces. For reproducing, run the tests/plugins/sink.ctf.fs/test_create_lttng_index.py test and open any of the generated CTF files in trace-compass. I explicitly tested and reproduced it with "with-packets-ctf-2" and "no-packets-ctf-2". The traces itself are valid, which can be proved by removing the index file and successfully re-opening them in trace-compass. PS: I'm pretty sure this is a trace-compass bug, but as I'm not a member of the tracecompass-dev ML, I report it here. Feel free to forward. Best regards, Felix Moessbauer -- Siemens AG Linux Expert Center Friedrich-Ludwig-Bauer-Str. 3 85748 Garching, Germany