gh-123014: Disable pidfd API on older Android versions (#124458)

Doc/library/os.rst

@@ -4602,7 +4602,7 @@ written in Python, such as a mail server's external command delivery program.
 
    See the :manpage:`pidfd_open(2)` man page for more details.
 
-   .. availability:: Linux >= 5.3
+   .. availability:: Linux >= 5.3, Android >= :func:`build-time <sys.getandroidapilevel>` API level 31
    .. versionadded:: 3.9
 
    .. data:: PIDFD_NONBLOCK

Doc/library/signal.rst

@@ -411,7 +411,7 @@ The :mod:`signal` module defines the following functions:
 
    See the :manpage:`pidfd_send_signal(2)` man page for more information.
 
-   .. availability:: Linux >= 5.1
+   .. availability:: Linux >= 5.1, Android >= :func:`build-time <sys.getandroidapilevel>` API level 31
    .. versionadded:: 3.9
 
 

Misc/NEWS.d/next/Library/2024-09-24-19-32-14.gh-issue-123014.zVcfkZ.rst

@@ -0,0 +1,3 @@
+:func:`os.pidfd_open` and :func:`signal.pidfd_send_signal` are now
+unavailable when building against Android API levels older than 31, since
+the underlying system calls may cause a crash.

Modules/clinic/posixmodule.c.h

@@ -5954,7 +5954,7 @@ os_wait(PyObject *module, PyObject *Py_UNUSED(ignored))
 
 #endif /* defined(HAVE_WAIT) */
 
-#if (defined(__linux__) && defined(__NR_pidfd_open))
+#if (defined(__linux__) && defined(__NR_pidfd_open) && !(defined(__ANDROID__) && __ANDROID_API__ < 31))
 
 PyDoc_STRVAR(os_pidfd_open__doc__,
 "pidfd_open($module, /, pid, flags=0)\n"
@@ -6013,7 +6013,7 @@ exit:
     return return_value;
 }
 
-#endif /* (defined(__linux__) && defined(__NR_pidfd_open)) */
+#endif /* (defined(__linux__) && defined(__NR_pidfd_open) && !(defined(__ANDROID__) && __ANDROID_API__ < 31)) */
 
 #if defined(HAVE_SETNS)
 
@@ -12837,4 +12837,4 @@ os__create_environ(PyObject *module, PyObject *Py_UNUSED(ignored))
 #ifndef OS__SUPPORTS_VIRTUAL_TERMINAL_METHODDEF
     #define OS__SUPPORTS_VIRTUAL_TERMINAL_METHODDEF
 #endif /* !defined(OS__SUPPORTS_VIRTUAL_TERMINAL_METHODDEF) */
-/*[clinic end generated code: output=a736ad3f7205176e input=a9049054013a1b77]*/
+/*[clinic end generated code: output=b93bbaaa8eb5b0ce input=a9049054013a1b77]*/

Modules/clinic/signalmodule.c.h

@@ -670,7 +670,7 @@ exit:
 
 #endif /* defined(HAVE_PTHREAD_KILL) */
 
-#if (defined(__linux__) && defined(__NR_pidfd_send_signal))
+#if (defined(__linux__) && defined(__NR_pidfd_send_signal) && !(defined(__ANDROID__) && __ANDROID_API__ < 31))
 
 PyDoc_STRVAR(signal_pidfd_send_signal__doc__,
 "pidfd_send_signal($module, pidfd, signalnum, siginfo=None, flags=0, /)\n"
@@ -723,7 +723,7 @@ exit:
     return return_value;
 }
 
-#endif /* (defined(__linux__) && defined(__NR_pidfd_send_signal)) */
+#endif /* (defined(__linux__) && defined(__NR_pidfd_send_signal) && !(defined(__ANDROID__) && __ANDROID_API__ < 31)) */
 
 #ifndef SIGNAL_ALARM_METHODDEF
     #define SIGNAL_ALARM_METHODDEF
@@ -776,4 +776,4 @@ exit:
 #ifndef SIGNAL_PIDFD_SEND_SIGNAL_METHODDEF
     #define SIGNAL_PIDFD_SEND_SIGNAL_METHODDEF
 #endif /* !defined(SIGNAL_PIDFD_SEND_SIGNAL_METHODDEF) */
-/*[clinic end generated code: output=6d8e17a32cef668f input=a9049054013a1b77]*/
+/*[clinic end generated code: output=c57b4b98fad6f4b8 input=a9049054013a1b77]*/

Modules/posixmodule.c

@@ -10121,7 +10121,10 @@ os_wait_impl(PyObject *module)
 }
 #endif /* HAVE_WAIT */
 
-#if defined(__linux__) && defined(__NR_pidfd_open)
+
+// This system call always crashes on older Android versions.
+#if defined(__linux__) && defined(__NR_pidfd_open) && \
+    !(defined(__ANDROID__) && __ANDROID_API__ < 31)
 /*[clinic input]
 os.pidfd_open
   pid: pid_t

Modules/signalmodule.c

@@ -1299,7 +1299,9 @@ signal_pthread_kill_impl(PyObject *module, unsigned long thread_id,
 #endif   /* #if defined(HAVE_PTHREAD_KILL) */
 
 
-#if defined(__linux__) && defined(__NR_pidfd_send_signal)
+// This system call always crashes on older Android versions.
+#if defined(__linux__) && defined(__NR_pidfd_send_signal) && \
+    !(defined(__ANDROID__) && __ANDROID_API__ < 31)
 /*[clinic input]
 signal.pidfd_send_signal