QUERY · ISSUE

Hang when accessing filesystem if using timers/interrupts

openby rkarlsbaopened 2021-05-01updated 2022-02-21

bugport-rp2

Hi all

I have an rpi pico loaded with micropython and I have this issue detailed on the links below

https://www.raspberrypi.org/forums/viewtopic.php?f=146&t=310648
https://forum.micropython.org/viewtopic.php?f=21&t=10430

It is reproducable on current micropython by others and it seems to be a bug. Please help :)

CANDIDATE · ISSUE

USB problem on RPi pico

openby davehylandsopened 2021-01-29updated 2022-04-30

port-rp2

I have an issue with rshell that seems to be caused by the USB comms.

If I issue the command cp ports/rp2/examples/* /pyboard then rshell will hang, typically on the first file.

If I add some statements in the recv_file_from_host function in rshell (this is the part that runs on the pico) that opens a UART and logs some additional information to the UART, then the copies all succeed.

I tried adding 20 msec delays each place that there was log statement, but that doesn't seem to make things work either.

Sorry I don't have a simpler test case, but I figured I'd log the issue and see if I can create a simple program which reproduces the hang/crash.

Sometimes, things hang, and sometimes the serial port is forcibly closed (I suspect that this might be a crash on the pico side).

Assessment

S Sonnet · medium

Both issues involve hangs on RP2/Raspberry Pi Pico with timing-sensitive characteristics, but they describe different scenarios. #7204 is specifically about filesystem access deadlocking when timer/interrupt handlers are active in user code. #6816 is about USB communication hanging during rshell file transfers, where the timing sensitivity (UART logging resolves it) suggests a race condition in the USB stack. There is a plausible common root cause — USB on RP2 may use interrupts internally, so #6816's hang could be a manifestation of the same interrupt/filesystem synchronization issue described in #7204. However, #6816's description focuses on host-side file transfer via rshell and does not mention user timers or interrupts, making the connection speculative rather than established. Neither issue resolves the other.

Suggested action

Link the two issues for cross-reference. If the interrupt/filesystem race condition described in #7204 is diagnosed and fixed, verify whether it also resolves the USB hang in #6816 before closing either. Do not close either issue at this stage.

Hang when accessing filesystem if using timers/interrupts

USB problem on RPi pico

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