Crash report

What happened?

This one is a bit niche! It also needs a python compiled with --with-dtrace

probe.d:

python$target:::import-find-load-start
{
    printf("import probe fired\n");
}

test.py:

try:
  __import__('\ud800')
except:
  pass

> sudo dtrace -q -s probe.d -c './python.exe test.py'

Assertion failed: (!_PyErr_Occurred(tstate)), function _PyEval_EvalFrameDefault, file generated_cases.c.h, line 13858.
import probe fired
import probe fired
import probe fired
...

The import dtrace hooks pass call PyUnicode_AsUTF8 and pass the value to the probe without checking if the conversion succeeded, now dtrace doesn't seem to mind getting a null pointer (I don't know much about how that bit works tbh), but a stale exception is left around which triggers a debug assert:

CPython versions tested on:

CPython main branch

Operating systems tested on:

macOS

Output from running 'python -VV' on the command line:

Python 3.16.0a0 (heads/main:e8158d1a02d, Aug 20 2026, 15:09:24) [Clang 21.0.0 (clang-2100.3.27.1)]

Linked PRs

• gh-156118: Fix DTrace probes with names that cannot be encoded #158127