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gh-137838: Fix JIT trace buffer overrun by increasing possible exit stubs (gh-138177)

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Donghee Na 2025-09-09 09:51:08 +09:00 • committed by GitHub
parent 03ee060ec8
commit 5edfe55acf
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5 changed files with 19 additions and 6 deletions
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2
Include/internal/pycore_optimizer.h
View file

@ -119,7 +119,7 @@ PyAPI_FUNC(void) _Py_Executors_InvalidateCold(PyInterpreterState *interp);
#define JIT_CLEANUP_THRESHOLD 100000
// This is the length of the trace we project initially.
#define UOP_MAX_TRACE_LENGTH 800
#define UOP_MAX_TRACE_LENGTH 1200
#define TRACE_STACK_SIZE 5

2
Lib/test/test_sys_settrace.py
View file

@ -360,6 +360,8 @@ class TraceTestCase(unittest.TestCase):
# Disable gc collection when tracing, otherwise the
# deallocators may be traced as well.
def setUp(self):
if os.environ.get('PYTHON_UOPS_OPTIMIZE') == '0':
self.skipTest("Line tracing behavior differs when JIT optimizer is disabled")
self.using_gc = gc.isenabled()
gc.disable()
self.addCleanup(sys.settrace, sys.gettrace())

6
Lib/test/test_trace.py
View file

@ -142,6 +142,8 @@ def test_traced_func_linear(self):
self.assertEqual(self.tracer.results().counts, expected)
@unittest.skipIf(os.environ.get('PYTHON_UOPS_OPTIMIZE') == '0',
"Line counts differ when JIT optimizer is disabled")
def test_traced_func_loop(self):
self.tracer.runfunc(traced_func_loop, 2, 3)
@ -166,6 +168,8 @@ def test_traced_func_importing(self):
self.assertEqual(self.tracer.results().counts, expected)
@unittest.skipIf(os.environ.get('PYTHON_UOPS_OPTIMIZE') == '0',
"Line counts differ when JIT optimizer is disabled")
def test_trace_func_generator(self):
self.tracer.runfunc(traced_func_calling_generator)
@ -236,6 +240,8 @@ def setUp(self):
self.my_py_filename = fix_ext_py(__file__)
self.addCleanup(sys.settrace, sys.gettrace())
@unittest.skipIf(os.environ.get('PYTHON_UOPS_OPTIMIZE') == '0',
"Line counts differ when JIT optimizer is disabled")
def test_exec_counts(self):
self.tracer = Trace(count=1, trace=0, countfuncs=0, countcallers=0)
code = r'''traced_func_loop(2, 5)'''

2
Misc/NEWS.d/next/Core_and_Builtins/2025-08-27-17-51-38.gh-issue-137838.lK6T0j.rst Normal file
View file

@ -0,0 +1,2 @@
Fix JIT trace buffer overrun by increasing possible exit stubs.
Patch by Donghee Na.

13
Python/optimizer.c
View file

@ -591,9 +591,8 @@ translate_bytecode_to_trace(
for (;;) {
target = INSTR_IP(instr, code);
// Need space for _DEOPT
max_length--;
// One for possible _DEOPT, one because _CHECK_VALIDITY itself might _DEOPT
max_length-=2;
uint32_t opcode = instr->op.code;
uint32_t oparg = instr->op.arg;
@ -1283,6 +1282,11 @@ uop_optimize(
_Py_BloomFilter_Init(&dependencies);
_PyUOpInstruction buffer[UOP_MAX_TRACE_LENGTH];
OPT_STAT_INC(attempts);
char *env_var = Py_GETENV("PYTHON_UOPS_OPTIMIZE");
bool is_noopt = true;
if (env_var == NULL || *env_var == '\0' || *env_var > '0') {
is_noopt = false;
}
int length = translate_bytecode_to_trace(frame, instr, buffer, UOP_MAX_TRACE_LENGTH, &dependencies, progress_needed);
if (length <= 0) {
// Error or nothing translated
@ -1290,8 +1294,7 @@ uop_optimize(
}
assert(length < UOP_MAX_TRACE_LENGTH);
OPT_STAT_INC(traces_created);
char *env_var = Py_GETENV("PYTHON_UOPS_OPTIMIZE");
if (env_var == NULL || *env_var == '\0' || *env_var > '0') {
if (!is_noopt) {
length = _Py_uop_analyze_and_optimize(frame, buffer,
length,
curr_stackentries, &dependencies);