python · ambv · Sep 16, 2025 · Aug 25, 2025 · Aug 25, 2025 · Aug 25, 2025
@@ -336,7 +336,14 @@ def prepare(self):
         raw.lflag |= termios.ISIG
         raw.cc[termios.VMIN] = 1
         raw.cc[termios.VTIME] = 0
-        tcsetattr(self.input_fd, termios.TCSADRAIN, raw)
+        try:
+            tcsetattr(self.input_fd, termios.TCSADRAIN, raw)
+        except termios.error as e:
+            if e.args[0] != errno.EIO:
+                # gh-135329: when running under external programs (like strace),
+                # tcsetattr may fail with EIO. We can safely ignore this
+                # and continue with default terminal settings.
+                raise
 
         # In macOS terminal we need to deactivate line wrap via ANSI escape code
         if platform.system() == "Darwin" and os.getenv("TERM_PROGRAM") == "Apple_Terminal":
@@ -368,7 +375,11 @@ def restore(self):
         self.__disable_bracketed_paste()
         self.__maybe_write_code(self._rmkx)
         self.flushoutput()
-        tcsetattr(self.input_fd, termios.TCSADRAIN, self.__svtermstate)
+        try:
+            tcsetattr(self.input_fd, termios.TCSADRAIN, self.__svtermstate)
+        except termios.error as e:
+            if e.args[0] != errno.EIO:
+                raise
 
         if platform.system() == "Darwin" and os.getenv("TERM_PROGRAM") == "Apple_Terminal":
             os.write(self.output_fd, b"\033[?7h")
@@ -407,6 +418,9 @@ def get_event(self, block: bool = True) -> Event | None:
                             return self.event_queue.get()
                         else:
                             continue
+                    elif err.errno == errno.EIO:
+                        import sys
+                        sys.exit(errno.EIO)
                     else:
                         raise
                 else:

@@ -2,11 +2,17 @@
 import os
 import sys
 import unittest
+import errno
+import termios
 from functools import partial
 from test.support import os_helper, force_not_colorized_test_class
+import subprocess
+import time
+import shutil
+import signal
 
 from unittest import TestCase
-from unittest.mock import MagicMock, call, patch, ANY
+from unittest.mock import MagicMock, call, patch, ANY, Mock
 
 from .support import handle_all_events, code_to_events
 
@@ -303,3 +309,109 @@ def test_getheightwidth_with_invalid_environ(self, _os_write):
             self.assertIsInstance(console.getheightwidth(), tuple)
             os.environ = []
             self.assertIsInstance(console.getheightwidth(), tuple)
+
+
+class TestUnixConsoleEIOHandling(TestCase):
+
+    @patch('_pyrepl.unix_console.tcsetattr')
+    @patch('_pyrepl.unix_console.tcgetattr')
+    def test_eio_error_handling_in_prepare(self, mock_tcgetattr, mock_tcsetattr):
+        mock_termios = Mock()
+        mock_termios.iflag = 0
+        mock_termios.oflag = 0
+        mock_termios.cflag = 0
+        mock_termios.lflag = 0
+        mock_termios.cc = [0] * 32
+        mock_termios.copy.return_value = mock_termios
+        mock_tcgetattr.return_value = mock_termios
+
+        mock_tcsetattr.side_effect = termios.error(errno.EIO, "Input/output error")
+
+        console = UnixConsole(term="xterm")
+
+        try:
+            console.prepare()
+        except termios.error as e:
+            if e.args[0] == errno.EIO:
+                self.fail("EIO error should have been handled gracefully in prepare()")
+            raise
+
+    @patch('_pyrepl.unix_console.tcsetattr')
+    @patch('_pyrepl.unix_console.tcgetattr')
+    def test_eio_error_handling_in_restore(self, mock_tcgetattr, mock_tcsetattr):
+
+        mock_termios = Mock()
+        mock_termios.iflag = 0
+        mock_termios.oflag = 0
+        mock_termios.cflag = 0
+        mock_termios.lflag = 0
+        mock_termios.cc = [0] * 32
+        mock_termios.copy.return_value = mock_termios
+        mock_tcgetattr.return_value = mock_termios
+
+        console = UnixConsole(term="xterm")
+        console.prepare()
+
+        mock_tcsetattr.side_effect = termios.error(errno.EIO, "Input/output error")
+
+        try:
+            console.restore()
+        except termios.error as e:
+            if e.args[0] == errno.EIO:
+                self.fail("EIO error should have been handled gracefully in restore()")
+            raise
+
+class TestEIOWithStrace(unittest.TestCase):
+    def setUp(self):
+        self.strace = shutil.which("strace")
+        if not self.strace:
+            self.skipTest("strace")
+
+    def _attach_strace(self, pid):
+        cmd = [self.strace, "-qq", "-p", str(pid), "-e", "inject=read:error=EIO:when=1", "-o", "/dev/null"]
+        try:
+            p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)
+            time.sleep(0.15)
+            if p.poll() is None:
+                return p
+        except Exception:
+            pass
+
+        cmd = [self.strace, "-qq", "-p", str(pid), "-e", "fault=read:error=EIO:when=1", "-o", "/dev/null"]
+        p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)
+        time.sleep(0.15)
+        return p
+
+    def test_repl_eio(self):
+        pybin = sys.executable
+
+        child_code = r"""
+import signal, sys
+signal.signal(signal.SIGUSR1, lambda *a: None)
+print("READY", flush=True)
+signal.pause()
+input()
+"""
+
+        proc = subprocess.Popen(
+            [pybin, "-S", "-c", child_code],
+            stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            text=True
+        )
+
+        line = proc.stdout.readline().strip()
+        self.assertEqual(line, "READY")
+
+        tracer = self._attach_strace(proc.pid)
+
+        try:
+            os.kill(proc.pid, signal.SIGUSR1)
+            _, err = proc.communicate(timeout=5)
+        finally:
+            if tracer and tracer.poll() is None:
+                tracer.terminate()
+
+        self.assertNotEqual(proc.returncode, 0)
+        self.assertTrue("Errno 5" in err or "Input/output error" in err or "EOFError" in err, err)
diff --git a/Misc/NEWS.d/next/Library/2025-08-25-18-06-04.gh-issue-138133.Zh9rGo.rst b/Misc/NEWS.d/next/Library/2025-08-25-18-06-04.gh-issue-138133.Zh9rGo.rst
@@ -0,0 +1 @@
+Prevent infinite traceback loop when sending CTRL^C to Python through ``strace``.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Prevent infinite traceback loop when sending CTRL^C to Python through ``strace``.