Bug report

Bug description:

importsysdeff(*args):passdefbar():yield42sys.settrace(f)g=bar()next(g)

The code above will trigger an assertion added in#109846.

python: Python/instrumentation.c:1576: _Py_Instrument: Assertion `(interp->ceval.eval_breaker & ~_PY_EVAL_EVENTS_MASK) == 0 || instrumentation_cross_checks(interp, code)' failed.Aborted

The reason is that during the interpreter finalization, the global event monitors are reset to 0. However, the garbage collection triggered a send to the generatorbar which then triggered_Py_Instrument.

is_version_up_to_date is true because the the code was instrumented when last timeeval_breaker changed. However,instrumentation_cross_checks would fail, becauseinterp->monitors is reset to0.

Notice that in the code example above, if the trace functionf returns itself rather thanNone, the assertion failure won't trigger because the generator would not be garbage collected - this might be an instrumentation bug that made the generator uncollectable (I've confirmed that_PyGen_Finalize andgen_close() never executed). However, I did not connect the dots so I don't know why that did not work.

I've made a simple patch in the PR, where I reset theinterp->ceval.eval_breaker = 0 ininterpreter_clear. It's kind of reasonable but I'm not knowledgeable enough to be confident that this is the/a correct fix.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-110752: Resetceval.eval_breaker to 0 ininterpreter_clear #110753