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bpo-38070: Py_FatalError() logs runtime state #16246

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Merged
merged 3 commits into from
Sep 17, 2019
Merged

bpo-38070: Py_FatalError() logs runtime state #16246

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67c60c5
bpo-38070: Py_FatalError() logs runtime state
vstinner Sep 17, 2019
f180f5e
Update test_capi
vstinner Sep 17, 2019
a54bfe2
Update test_faulthandler
vstinner Sep 17, 2019
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2 changes: 2 additions & 0 deletions Lib/test/test_capi.py
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Original file line number Diff line number Diff line change
Expand Up @@ -198,6 +198,7 @@ def test_return_null_without_error(self):
self.assertRegex(err.replace(b'\r', b''),
br'Fatal Python error: a function returned NULL '
br'without setting an error\n'
br'Python runtime state: initialized\n'
br'SystemError: <built-in function '
br'return_null_without_error> returned NULL '
br'without setting an error\n'
Expand Down Expand Up @@ -225,6 +226,7 @@ def test_return_result_with_error(self):
self.assertRegex(err.replace(b'\r', b''),
br'Fatal Python error: a function returned a '
br'result with an error set\n'
br'Python runtime state: initialized\n'
br'ValueError\n'
br'\n'
br'The above exception was the direct cause '
Expand Down
18 changes: 12 additions & 6 deletions Lib/test/test_faulthandler.py
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Original file line number Diff line number Diff line change
Expand Up @@ -90,7 +90,8 @@ def get_output(self, code, filename=None, fd=None):

def check_error(self, code, line_number, fatal_error, *,
filename=None, all_threads=True, other_regex=None,
fd=None, know_current_thread=True):
fd=None, know_current_thread=True,
py_fatal_error=False):
"""
Check that the fault handler for fatal errors is enabled and check the
traceback from the child process output.
Expand All @@ -110,10 +111,12 @@ def check_error(self, code, line_number, fatal_error, *,
{header} \(most recent call first\):
File "<string>", line {lineno} in <module>
"""
regex = dedent(regex.format(
if py_fatal_error:
fatal_error += "\nPython runtime state: initialized"
regex = dedent(regex).format(
lineno=line_number,
fatal_error=fatal_error,
header=header)).strip()
header=header).strip()
if other_regex:
regex += '|' + other_regex
output, exitcode = self.get_output(code, filename=filename, fd=fd)
Expand Down Expand Up @@ -170,7 +173,8 @@ def test_fatal_error_c_thread(self):
""",
3,
'in new thread',
know_current_thread=False)
know_current_thread=False,
py_fatal_error=True)

def test_sigabrt(self):
self.check_fatal_error("""
Expand Down Expand Up @@ -226,15 +230,17 @@ def test_fatal_error(self):
faulthandler._fatal_error(b'xyz')
""",
2,
'xyz')
'xyz',
py_fatal_error=True)

def test_fatal_error_without_gil(self):
self.check_fatal_error("""
import faulthandler
faulthandler._fatal_error(b'xyz', True)
""",
2,
'xyz')
'xyz',
py_fatal_error=True)

@unittest.skipIf(sys.platform.startswith('openbsd'),
"Issue #12868: sigaltstack() doesn't work on "
Expand Down
85 changes: 59 additions & 26 deletions Python/pylifecycle.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1975,13 +1975,14 @@ init_sys_streams(PyThreadState *tstate)


static void
_Py_FatalError_DumpTracebacks(int fd)
_Py_FatalError_DumpTracebacks(int fd, PyInterpreterState *interp,
PyThreadState *tstate)
{
fputc('\n', stderr);
fflush(stderr);

/* display the current Python stack */
_Py_DumpTracebackThreads(fd, NULL, NULL);
_Py_DumpTracebackThreads(fd, interp, tstate);
}

/* Print the current exception (if an exception is set) with its traceback,
Expand Down Expand Up @@ -2079,10 +2080,39 @@ fatal_output_debug(const char *msg)
}
#endif


static void
fatal_error_dump_runtime(FILE *stream, _PyRuntimeState *runtime)
{
fprintf(stream, "Python runtime state: ");
if (runtime->finalizing) {
fprintf(stream, "finalizing (tstate=%p)", runtime->finalizing);
}
else if (runtime->initialized) {
fprintf(stream, "initialized");
}
else if (runtime->core_initialized) {
fprintf(stream, "core initialized");
}
else if (runtime->preinitialized) {
fprintf(stream, "preinitialized");
}
else if (runtime->preinitializing) {
fprintf(stream, "preinitializing");
}
else {
fprintf(stream, "unknown");
}
fprintf(stream, "\n");
fflush(stream);
}


static void _Py_NO_RETURN
fatal_error(const char *prefix, const char *msg, int status)
{
const int fd = fileno(stderr);
FILE *stream = stderr;
const int fd = fileno(stream);
static int reentrant = 0;

if (reentrant) {
Expand All @@ -2092,45 +2122,48 @@ fatal_error(const char *prefix, const char *msg, int status)
}
reentrant = 1;

fprintf(stderr, "Fatal Python error: ");
fprintf(stream, "Fatal Python error: ");
if (prefix) {
fputs(prefix, stderr);
fputs(": ", stderr);
fputs(prefix, stream);
fputs(": ", stream);
}
if (msg) {
fputs(msg, stderr);
fputs(msg, stream);
}
else {
fprintf(stderr, "<message not set>");
fprintf(stream, "<message not set>");
}
fputs("\n", stderr);
fflush(stderr); /* it helps in Windows debug build */
fputs("\n", stream);
fflush(stream); /* it helps in Windows debug build */

/* Check if the current thread has a Python thread state
and holds the GIL */
PyThreadState *tss_tstate = PyGILState_GetThisThreadState();
if (tss_tstate != NULL) {
PyThreadState *tstate = _PyThreadState_GET();
if (tss_tstate != tstate) {
/* The Python thread does not hold the GIL */
tss_tstate = NULL;
}
}
else {
/* Py_FatalError() has been called from a C thread
which has no Python thread state. */
_PyRuntimeState *runtime = &_PyRuntime;
fatal_error_dump_runtime(stream, runtime);

PyThreadState *tstate = _PyRuntimeState_GetThreadState(runtime);
PyInterpreterState *interp = NULL;
if (tstate != NULL) {
interp = tstate->interp;
}
int has_tstate_and_gil = (tss_tstate != NULL);

/* Check if the current thread has a Python thread state
and holds the GIL.

tss_tstate is NULL if Py_FatalError() is called from a C thread which
has no Python thread state.

tss_tstate != tstate if the current Python thread does not hold the GIL.
*/
PyThreadState *tss_tstate = PyGILState_GetThisThreadState();
int has_tstate_and_gil = (tss_tstate != NULL && tss_tstate == tstate);
if (has_tstate_and_gil) {
/* If an exception is set, print the exception with its traceback */
if (!_Py_FatalError_PrintExc(fd)) {
/* No exception is set, or an exception is set without traceback */
_Py_FatalError_DumpTracebacks(fd);
_Py_FatalError_DumpTracebacks(fd, interp, tss_tstate);
}
}
else {
_Py_FatalError_DumpTracebacks(fd);
_Py_FatalError_DumpTracebacks(fd, interp, tss_tstate);
}

/* The main purpose of faulthandler is to display the traceback.
Expand Down