[lttng-dev] Problem setting a filter during enable-event, when done shortly after add-context

[David Goulet]

Hi Amit,

Can you please open an issue at bugs.lttng.org so we can have a trace of the
issue somewhere along with the fix ?

Thanks!
David

Amit Margalit:
> Hi,
> 
> I seem to have a problem setting a filter during enable-event, which happens in
> a script immediately after add-context succeeds. The error is "Error: Invalid
> filter bytecode".
> 
> The sequence I am going through is in the following script excerpt:
> 
> lttng-sessiond with --no-kernel -v --verbose-consumer        >> logfile 2>&1
> lttng create samba -o /local/traces/lttng/20130625114835     >> logfile 2>&1
> lttng enable-channel channel0 -u \
>                         --tracefile-size ${LTTNG_MAX_TRACE_FILE_SIZE} \
>                         --tracefile-count ${LTTNG_MAX_FILES_PER_CORE} \
>                         --buffers-uid \
>                         --switch-timer 1000000 \
>                         --num-subbuf 16 \
>                         --subbuf-size 262144                 >> logfile 2>&1
> lttng add-context -u -t procname -s samba -c channel0        >> logfile 2>&1
> lttng enable-event -u -a --filter '$ctx.procname == "smbd" || $ctx.procname ==
> "winbindd"'
> 
> The output is shown here (with the enable-event command-line reproduced:
> 
> Session samba created.
> Traces will be written in /local/traces/lttng/20130625114835
> UST channel channel0 enabled for session samba
> UST context procname added to channel channel0
> /usr/bin/lttng enable-event -u -a --filter '$ctx.procname=="smbd" ||
> $ctx.procname=="winbindd"'
> error syntax error
> Parse error
> Error: Invalid filter bytecode
> 
> If I try to wait after the failure for some time, I can run lttng disable-event
> -u -a, and re-run the enable-event with the filter successfully. But I tried to
> put the disable-event command in the script and that didn't help - i.e. the
> "disable-event" command worked, but the enable-event with filter still failed in
> the same way.
> 
> Suggestions?
> 
> Thanks,
> 
> Amit Margalit
> IBM XIV - /Storage Reinvented/
> XIV-NAS Development Team
> Tel. 03-689-7774
> Fax. 03-689-7230
> 
> 
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