Bug #1170
closedUsing the --output flag with the new dynamic tracing feature in 2.11 causes the trace to be lost / no output produced
100%
Description
Running the example provided in the release notes (https://github.com/lttng/lttng-tools/releases/tag/v2.11.0-rc1), I believe I found a bug when setting a custom trace output path.
The following worked as expected. The trace was written to the default location (lttng-traces/demo-session-<timestamp>).
sudo lttng create demo-session
sudo lttng enable-event --kernel --userspace-probe /lib/x86_64-linux-gnu/libc-2.23.so:malloc libc_malloc
sudo lttng start
[do various actions]
sudo lttng stop
sudo lttng destroy
The following resulted in no trace file being produced:
sudo lttng create demo-session --output=/tmp/demo-session
sudo lttng enable-event --kernel --userspace-probe /lib/x86_64-linux-gnu/libc-2.23.so:malloc libc_malloc
sudo lttng start
[do various actions]
sudo lttng stop
sudo lttng destroy
The problem also applied if I set it to use the default directory:
sudo lttng create demo-session --output=/lttng-traces/demo-session
sudo lttng enable-event --kernel --userspace-probe /lib/x86_64-linux-gnu/libc-2.23.so:malloc libc_malloc
sudo lttng start
[do various actions]
sudo lttng stop
sudo lttng destroy
I am expecting to be able to set a custom output path based on the 2.10 documentation (https://lttng.org/docs/v2.10/#doc-tracing-the-linux-kernel)
I made sure to do exactly the same actions for each test.
Updated by Mathieu Desnoyers almost 6 years ago
- Project changed from LTTng-modules to LTTng-tools
Updated by Francis Deslauriers almost 6 years ago
Hi Deborah,
Thanks for the report. Could you simply try to same commands you run in steps 2 and 3 but replacing the enable-event command with the following
lttng enable-event -a -k
I want to know if it's related specifically to the new --userspace-probe feature or not.
Also, I don't know if it was a typo when you filed the bug report but the path you supplied for your 3rd testcase has a missing `~` to be the default $HOME/lttng-traces directory.
Cheers,
Updated by Deborah Barnard almost 6 years ago
My apologies. I was a little trigger-happy with the bug report.
Updated by Francis Deslauriers almost 6 years ago
Deborah Barnard wrote:
My apologies. I was a little trigger-happy with the bug report.
What do you mean? You fixed the issue?
Updated by Deborah Barnard almost 6 years ago
Yes - it was very much a human error. Sorry again!