[need help] Uprobe with perf_event Support

[yidaaichixia]

Description‌:
When testing BPFTime v0.0.3, I encountered issues with uprobe using perf_event. While a simple binary works when executed directly (able to poll perf_event content), it fails to poll any content when running under BPFTime - the operation simply hangs without any error messages.

‌Additional Context‌:
The agent attaches to an already running process (not started a new process)

Unclear whether this is an unsupported feature or if there are specific implementation requirements
Need clarification on:
Does BPFTime v0.0.3 fully support perf_event with uprobe in my situation?
Are there any special considerations for the implementation?

[yunwei37]

Hi @yidaaichixia , could you share your test program?

[yidaaichixia]

Thank you for your interest in my approach. Due to certain constraints, I'm unable to share the exact code, but here's the technical summary:

I implemented this by attaching uprobe hooks to a common method similar to DPVS processes. The user program follows a pattern comparable to the sslsniff example - in fact, I initially tested with sslsniff's sample code.

One particular observation: When modifying the wget command into a loop within a persistent process (unlike the original start-triggered wget), I found that perf_event couldn't capture data in this attach-triggered scenario.

Regarding debugging, I attempted to check bpftime logs but encountered challenges in the attach context - the handle appears to be exclusively operated by the business process, preventing spdlog output. As an alternative approach (which I haven't tested yet), I'm considering using syslog to bypass stdout for bpftime log inspection.

Would be happy to discuss any specific aspects further!