memory leak when calling ConnectHelper.get_all_connected_probes()

[maxschuh]

Issue: When calling ConnectHelper.get_all_connected_probes() multiple times memory consumption increases indefinitely.

System:

• Linux
• libusb-1.0.24-2
• python3.8, python3.9
• pyocd-0.28.3, pyocd-0.29.0

Steps to reproduce: >>> from pyocd.core.helpers import ConnectHelper >>> while True: >>> ... ConnectHelper.get_all_connected_probes(blocking=False)

I also tried to call garbage the collector manually, however this didn't help. Presumably there is still a reference somewhere to something?! The background of the whole thing is, that I have a daemon that checks periodically for new probes and after some time the daemon occupies the whole memory.

[flit]

Thanks for reporting. Definitely an issue if you need to continually check for new probes!

I agree there's probably a reference left dangling somewhere. Hopefully it's not somewhere in pyusb that can't be easily fixed.

[flit]

What type(s) of probe(s) are you using? That could narrow down the possibilities.

[maxschuh]

The memory leak seems to be independent from the type of probe as there is a leak even if no probe is attached. However typically I use J-Link and/or ST-Link probes where the error also occurs.

[flit]

Very interesting, I'm surprised it leaks with no probe attached. That's very helpful.

[flit]

I can reproduce it on macOS 10.15 with one CMSIS-DAPv1 (hidapi), one CMSIS-DAPv2 (libusb), and an STLinkV2-1 (libusb).

It doesn't seem to leak when no probes are attached. I need to try it on Linux and Windows next, and start trying to narrow down the root cause.

[joncutting]

I also confirm this is happening, I have 3 Raspberry Pi Debug Probes attached and after making O(10) consecutive connections on a Raspberry Pi 3 I see the same MemoryError:

Traceback (most recent call last): File "/home/pi/sram/swdtest.py", line 366, in cycle_dut session = ConnectHelper.session_with_chosen_probe(unique_id = debug_id, File "/home/pi/sram/.env/lib/python3.9/site-packages/pyocd/core/helpers.py", line 257, in session_with_chosen_probe probe = ConnectHelper.choose_probe( File "/home/pi/sram/.env/lib/python3.9/site-packages/pyocd/core/helpers.py", line 154, in choose_probe allProbes = ConnectHelper.get_all_connected_probes(blocking=blocking, unique_id=unique_id) File "/home/pi/sram/.env/lib/python3.9/site-packages/pyocd/core/helpers.py", line 94, in get_all_connected_probes allProbes = DebugProbeAggregator.get_all_connected_probes(unique_id=unique_id) File "/home/pi/sram/.env/lib/python3.9/site-packages/pyocd/probe/aggregator.py", line 57, in get_all_connected_probes probe = cls.get_probe_with_id(unique_id, is_explicit) File "/home/pi/sram/.env/lib/python3.9/site-packages/pyocd/probe/jlink_probe.py", line 84, in get_probe_with_id jlink = cls._get_jlink() File "/home/pi/sram/.env/lib/python3.9/site-packages/pyocd/probe/jlink_probe.py", line 58, in _get_jlink return pylink.JLink( File "/home/pi/sram/.env/lib/python3.9/site-packages/pylink/jlink.py", line 293, in init lib = library.Library(use_tmpcpy=use_tmpcpy) File "/home/pi/sram/.env/lib/python3.9/site-packages/pylink/library.py", line 293, in init self.load_default() File "/home/pi/sram/.env/lib/python3.9/site-packages/pylink/library.py", line 351, in load_default return self.load(path) File "/home/pi/sram/.env/lib/python3.9/site-packages/pylink/library.py", line 401, in load outputfile.write(inputfile.read()) MemoryError