Actions
Bug #1392
openlttng view: Stream 0 is not declared in metadata
Start date:
09/27/2023
Due date:
% Done:
0%
Estimated time:
Description
While trying to capture UST events from a simple program, even though kernel events seem to be properly captured, UST events are not. Trace Compass cannot decode the UST data (but it can decode from the kernel channel).
The application is single-threaded, performs only disk and stdout I/O, nothing fancy. Compiled with -finstrument-functions, no optimizations, and with debugging symbols.
Session setup:
# lttng create # lttng enable-channel -u --subbuf-size=64M --num-subbuf=8 chan_ust # lttng enable-channel -k --subbuf-size=64M --num-subbuf=2 chan_kernel # lttng add-context -u -t vpid -t ip -t procname -t vtid -c chan_ust # lttng enable-event -u -a -c chan_ust # lttng enable-event -k -c chan_kernel --syscall --all # lttng enable-event -k -c chan_kernel lttng_statedump_block_device,lttng_statedump_file_descriptor,lttng_statedump_process_state,mm_page_alloc,mm_page_free,net_dev_xmit,netif_receive_skb,sched_pi_setprio,sched_process_exec,sched_process_fork,sched_switch,sched_wakeup,sched_waking,softirq_entry,softirq_exit,softirq_raise # lttng start (possibly excessive preloads, but these are from my notes, collecting data on Varnish Cache) # LTTNG_UST_BLOCKING_RETRY_TIMEOUT=-1 LD_PRELOAD=liblttng-ust-fd.so:liblttng-ust-fork.so:liblttng-ust-dl.so:liblttng-ust-cyg-profile.so:liblttng-ust-libc-wrapper.so:liblttng-ust-pthread-wrapper.so tests/test-playlist tests/playlist/bug_ffmpeg_1000-x20.m3u # lttng stop # lttng view > /dev/null [error] Stream 0 is not declared in metadata. [error] Stream 0 is not declared in metadata. [error] Stream 0 is not declared in metadata. [error] Stream 0 is not declared in metadata. [error] Stream 0 is not declared in metadata. [error] Stream 0 is not declared in metadata. [error] Stream 0 is not declared in metadata. [error] Stream 0 is not declared in metadata. [error] Stream 0 is not declared in metadata. [error] Stream 0 is not declared in metadata. [error] Stream 0 is not declared in metadata. [error] Stream 0 is not declared in metadata.Environment:
- lttng-modules-2.13.10 (from tarball)
- lttng-tools-2.13.11 (from tarball)
- lttng-ust-2.13.6 (from tarball)
- babeltrace (git; at
v1.5.11) - Linux kernel 6.6.0-rc1
- Slackware64-current, up-to-date as of 2023-09-26
- Trace Compass 9.1.0.202309200833
IRC snippet:
Sep/27 16:13:54 rnsanchez I'm trying to find out what I'm doing wrong.. I keep getting "[error] Stream 0 is not declared in metadata." in my captures. I guess this is making tracecompass not being able to show UST events (simple function enter-exit instrumentation) Sep/27 16:16:46 rnsanchez using my old notes, while checking https://lttng.org/docs/v2.13/#doc-liblttng-ust-cyg-profile and other sections Sep/27 16:18:25 jgalar rnsanchez: shot in the dark, but are you making sure the session is stopped or destroyed before reading the trace? Sep/27 16:18:28 rnsanchez if it helps knowing, events from kernel channel are fine and I can see them in tracecompass (the trace is huge) Sep/27 16:18:52 rnsanchez jgalar: yes, with lttng stop, then I copy the data from root to my user Sep/27 16:19:10 rnsanchez but I get that Stream 0 regardless.. it's from lttng view Sep/27 16:20:11 jgalar it sounds like a metadata flushing issue, any chance you can share the trace? (or at least, the metadata files) Sep/27 16:20:42 rnsanchez yes, sure. just a moment while I upload it Sep/27 16:20:48 jgalar okay thanks Sep/27 16:21:43 ebugden not sure if related, but it's triggering deja vu of this issue: https://github.com/efficios/barectf/commit/d024537859c1d869bfa1cedc8abe8e3f7a648faa Sep/27 16:22:23 ebugden maybe a similar problem in a similar area in lttng view Sep/27 16:25:28 rnsanchez jgalar: https://rnsanchez.wait4.org/auto-20230927-161138.tar.xz Sep/27 16:27:33 rnsanchez jgalar: this last one has incomplete events as I was trying to investigate, but I can bundle another one with full events as I used to collect Sep/27 16:31:51 rnsanchez ebugden: is there anything on my side I can do? Sep/27 16:34:38 ebugden rnsanchez: i don't feel i'm familiar enough with this situation to say; i was tossing out the association as possible food for thought for jgalar Sep/27 16:35:12 rnsanchez oh ok :-) Sep/27 16:43:03 rnsanchez jgalar: just in case, here is with full events: https://rnsanchez.wait4.org/auto-20230927-164014.tar.xz Sep/27 16:45:53 jgalar ebugden: yup, the errors are indeed similar Sep/27 16:50:59 jgalar hmm, the user space trace's metadata doesn't declare any stream class, that's... unexpected... Sep/27 16:51:14 jgalar which versions of lttng-ust and lttng-tools are you running? Sep/27 16:55:03 rnsanchez ust 2.13.6 (tarball) and tools 2.13.11 (tarball too) Sep/27 16:55:07 rnsanchez compiled today Sep/27 16:55:13 jgalar okay Sep/27 17:17:57 ebugden rnsanchez (cc: jgalar): would you open a bug report on https://bugs.lttng.org/ ? Sep/27 17:18:16 rnsanchez ebugden: sure Sep/27 17:19:21 ebugden thanks! (we have a few hypotheses, but we'd need more information about exactly how the trace is generated) Sep/27 17:19:58 jgalar rnsanchez: it's weird, the user space trace's stream files just have the packet headers... if you can reproduce the problem while running lttng-sessiond with the `-vvv --verbose-consumer` options to get the logs, it would be helpful Sep/27 17:20:47 rnsanchez I can try. I suppose I have to finish the sessiond already running and manually launch another? Sep/27 17:21:06 jgalar yep
Files
Actions