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Description
Crash report
I've been using eBPF with the static markers in Python 3.10 and wanted to try out 3.11 now that it is released.
But it seems that thefunction__entry andline markers are broken in 3.11.
Thefunction__entry probe simply does not fire into the eBPF program.
Theline probe crashes the interpreter.
I'm using BCC to load the eBPF program like this:
#!/usr/bin/python3import argparsefrom bcc import BPF, USDTparser = argparse.ArgumentParser()parser.add_argument("pid", type=int)args = parser.parse_args()program = """int trace_entry(struct pt_regs *ctx) { bpf_trace_printk("Entry:"); return 0;}int trace_return(struct pt_regs *ctx) { bpf_trace_printk("Return:"); return 0;}int trace_line(struct pt_regs *ctx) { bpf_trace_printk("Line:"); return 0;}"""usdt = USDT(pid=args.pid)usdt.enable_probe_or_bail("python:function__entry", 'trace_entry')usdt.enable_probe_or_bail("python:function__return", 'trace_return')usdt.enable_probe_or_bail("python:line", 'trace_line')bpf = BPF(text=program, usdt_contexts=[usdt] if usdt else [], debug=0)try: bpf.trace_print()except KeyboardInterrupt: exit()If I don't enable theline probe this is the output:
❯ sudo ./ebpf-test.py 80715b' python-80715 [001] d...1 6539.145626: bpf_trace_printk: Return:'The entry message is never printed.
Error messages
With theline probe enabled, this is the crash error:
❯ ./pythonPython 3.11.0+ (heads/3.11:57dd11038f, Oct 31 2022, 10:30:28) [GCC 11.3.0] on linuxType "help", "copyright", "credits" or "license" for more information.>>> print("Hello world!")python: Python/ceval.c:5620: _PyEval_EvalFrameDefault: Assertion `cframe.use_tracing' failed.[1] 80398 IOT instruction (core dumped) ./pythonExpected result
Running the same test in 3.10.6 I get this result, as expected:
❯ python3 Python 3.10.6 (main, Aug 10 2022, 11:40:04) [GCC 11.3.0] on linuxType "help", "copyright", "credits" or "license" for more information.>>> print("Hello world!")Hello world!❯ sudo ./ebpf-test.py 81962b' python3-81962 [003] d...1 6907.857690: bpf_trace_printk: Entry:'b' python3-81962 [003] d...1 6907.857710: bpf_trace_printk: Line:'b' python3-81962 [003] d...1 6907.857765: bpf_trace_printk: Return:'Your environment
I used the head of the 3.11 branch with./configure --with-dtrace --with-pydebug
On Ubuntu 22.04.