[lttng-dev] Odd behaviour of lttng 2.0 kernel event listing

Thibault, Daniel Daniel.Thibault at drdc-rddc.gc.ca
Mon Jan 23 17:37:30 EST 2012


   I've narrowed it down to lttng-ctl.ask_sessiond(): the first recv_data_sessiond() call expects 16 bytes (sizeof(llm)) and gets 16 bytes.  llm.data_size holds the payload size (in bytes), which is what the second recv_data_sessiond() call expects...But it receives only 15 984 bytes of the expected 41 208.  The problem is that ask_sessiond() then reports the asked-for size as what it returned, without checking if they match.  15 984 bytes is 19 event records and 78% of a 20th record, which is exactly what we see in the session log (events 21 onward are blank).

Daniel U. Thibault
R & D pour la défense Canada - Valcartier (RDDC Valcartier) / Defence R&D Canada - Valcartier (DRDC Valcartier)
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