Skip to content

GH-144688: Fix refleaks in JIT when optimization fails #145420

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
markshannon wants to merge 1 commit into
base: main
Choose a base branch
from
Open

GH-144688: Fix refleaks in JIT when optimization fails #145420

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 13 additions & 1 deletion Python/optimizer.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1076,12 +1076,19 @@ _PyJit_FinalizeTracing(PyThreadState *tstate, int err)
exit->temperature = initial_temperature_backoff_counter(&tstate->interp->opt_config);
}
}
// Clear all recorded values
_PyJitUopBuffer *buffer = &tracer->code_buffer;
for (_PyUOpInstruction *inst = buffer->start; inst < buffer->next; inst++) {
if (_PyUop_Flags[inst->opcode] & HAS_RECORDS_VALUE_FLAG) {
Copy link
Member

@Fidget-Spinner Fidget-Spinner Mar 2, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I think this means you can remove

        else if (_PyUop_Flags[opcode] & HAS_RECORDS_VALUE_FLAG) {
            Py_XDECREF((PyObject *)(uintptr_t)buffer[pc].operand0);
            buffer[pc].opcode = _NOP;
        }

in optimizer.c to avoid double work?

Copy link
Member Author

@markshannon markshannon Mar 3, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We don't do double work: https://github.com/python/cpython/pull/145420/changes#diff-de09f74c4306be5ef0284d665091976873569094d645a35b48467ea2a11d67f7R1531 and it is faster to leave the cleanup in the fixup pass as we have to do that pass anyway in the normal, non-error case.

Py_XDECREF((PyObject *)(uintptr_t)inst->operand0);
}
}
Py_CLEAR(tracer->initial_state.code);
Py_CLEAR(tracer->initial_state.func);
Py_CLEAR(tracer->initial_state.executor);
Py_CLEAR(tracer->prev_state.instr_code);
Py_CLEAR(tracer->prev_state.recorded_value);
uop_buffer_init(&tracer->code_buffer, &tracer->uop_array[0], UOP_MAX_TRACE_LENGTH);
uop_buffer_init(buffer, &tracer->uop_array[0], UOP_MAX_TRACE_LENGTH);
tracer->is_tracing = false;
}

Expand Down Expand Up @@ -1521,6 +1528,11 @@ uop_optimize(
}
assert(_PyOpcode_uop_name[buffer[pc].opcode]);
}
// We've cleaned up the references in the buffer, so discard the code buffer
// to avoid doing it again during tracer cleanup
_PyJitUopBuffer *code_buffer = &_tstate->jit_tracer_state->code_buffer;
code_buffer->next = code_buffer->start;

OPT_HIST(effective_trace_length(buffer, length), optimized_trace_length_hist);
_PyUOpInstruction *output = &_tstate->jit_tracer_state->uop_array[0];
length = stack_allocate(buffer, output, length);
Expand Down
Loading