Bug 475982

Summary:	pass signals to debugee
Product:	[Applications] Heaptrack	Reporter:	Hamish Moffatt <hamish+kde>
Component:	general	Assignee:	Milian Wolff <mail>
Status:	CONFIRMED ---
Severity:	normal
Priority:	NOR
Version First Reported In:	1.5.0
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Hamish Moffatt 2023-10-22 22:41:16 UTC

tl;dr: could heaptrack pass signals along to the debugee?

SUMMARY
I'm trying to debug a program which runs in a container. This program normally runs as the entrypoint of the container, but now I run it inside heaptrack. To stop the container, the runtime sends SIGINT or SIGTERM to the primary process, which would cleanly shut down my program but does not get passed through the heaptrack shell script.

Eventually the container runtime kills all the processes. As a result it looks like all the memory got leaked because the program did not go through a clean shutdown.

The same would apply if running heaptrack from a systemd unit.

STEPS TO REPRODUCE
1.  Run `heaptrack /usr/bin/sleep 60`
2.  Send SIGINT or SIGTERM to heaptrack

OBSERVED RESULT
heaptrack exits on SIGTERM but sleep is still running
SIGINT seems to be ignored completely

EXPECTED RESULT
SIGTERM is sent to debugee

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Debian bookworm + heaptrack 1.4.0 from package, or heaptrack 1.5.0 compiled from source

Comment 1 Milian Wolff 2023-10-28 07:43:41 UTC

I cannot reproduce this issue. First I did:

```
$ heaptrack sleep 5000
heaptrack output will be written to "/home/milian/projects/src/heaptrack/heaptrack.sleep.11782.zst"
starting application, this might take some time...
NOTE: heaptrack detected DEBUGINFOD_URLS but will disable it to prevent 
unintended network delays during recording
If you really want to use DEBUGINFOD, export HEAPTRACK_ENABLE_DEBUGINFOD=1
```

then I pressed `Ctrl+C` which stops the process then and opens up the UI. Sleep isn't running anymore at that point, only the heaptrack UI:

```
$ ps aux | grep sleep
milian     11782  0.0  0.0   8228  4164 pts/1    S+   09:41   0:00 /bin/sh /mnt/data1/milian/compiled/other/bin/heaptrack sleep 5000
milian     11912  5.1  0.6 5701264 228552 pts/1  Sl+  09:41   0:00 /mnt/data1/milian/compiled/other/bin/heaptrack_gui /home/milian/projects/src/heaptrack/heaptrack.sleep.11782.zst
milian     12035  0.0  0.0   6912  2420 pts/2    S+   09:41   0:00 grep --colour sleep
```

Comment 2 Hamish Moffatt 2023-10-28 07:50:57 UTC

(In reply to Milian Wolff from comment #1)
> then I pressed `Ctrl+C` which stops the process then and opens up the UI.
> Sleep isn't running anymore at that point, only the heaptrack UI:

But then your signal went straight to sleep. If you send it to heaptrack, heaptrack will exit leaving the debuggee running. This is what happens if you run it in a container or from systemd. Not only is the child still running, the analysis is wrong because the child didn't get to run a clean shutdown.

Comment 3 Milian Wolff 2023-10-30 08:32:09 UTC

ah, so:

```
$ heaptrack sleep 1000 &
[1] 8817
heaptrack output will be written to "/tmp/heaptrack.sleep.8817.zst"
starting application, this might take some time...
NOTE: heaptrack detected DEBUGINFOD_URLS but will disable it to prevent 
unintended network delays during recording
If you really want to use DEBUGINFOD, export HEAPTRACK_ENABLE_DEBUGINFOD=1

$ kill -SIGTERM 8817
```

Comment 4 Hamish Moffatt 2024-09-18 07:18:42 UTC

Hi,
Is there any news on this issue?
I needed to use heaptrack in a container again and ran into this same issue.

Comment 5 Hamish Moffatt 2024-09-18 09:03:55 UTC

Looking at the wrapper script, I could simply set LD_PRELOAD and DUMP_HEAPTRACK_OUTPUT to get the raw output in my container environment.

Anyway, I made the following modification to the code that starts the debuggee, and now it is passing the signals through:

if [ -z "$debug" ] && [ -z "$pid" ]; then
  echo "starting application, this might take some time..."
  trap 'kill -TERM ${target_pid}' TERM
  trap 'kill -INT ${target_pid}' INT
  LD_PRELOAD="$LIBHEAPTRACK_PRELOAD${LD_PRELOAD:+:$LD_PRELOAD}" DUMP_HEAPTRACK_OUTPUT="$pipe" "$client" "$@" &
  target_pid=$!
  wait $target_pid
  EXIT_CODE=$?
else