diff --git a/Lib/test/test_posix.py b/Lib/test/test_posix.py
index 148c064..dba50e0 100644
--- a/Lib/test/test_posix.py
+++ b/Lib/test/test_posix.py
@@ -298,6 +298,16 @@
         finally:
             os.close(fd)
 
+    # issue31106 - posix_fallocate() does not set error in errno.
+    @unittest.skipUnless(hasattr(posix, 'posix_fallocate'),
+        "test needs posix.posix_fallocate()")
+    def test_posix_fallocate_errno(self):
+        try:
+            posix.posix_fallocate(-42, 0, 10)
+        except OSError as inst:
+            if inst.errno != errno.EBADF:
+                raise
+
     @unittest.skipUnless(hasattr(posix, 'posix_fadvise'),
         "test needs posix.posix_fadvise()")
     def test_posix_fadvise(self):
@@ -307,6 +317,15 @@
         finally:
             os.close(fd)
 
+    @unittest.skipUnless(hasattr(posix, 'posix_fadvise'),
+        "test needs posix.posix_fadvise()")
+    def test_posix_fadvise_errno(self):
+        try:
+            posix.posix_fadvise(-42, 0, 0, posix.POSIX_FADV_WILLNEED)
+        except OSError as inst:
+            if inst.errno != errno.EBADF:
+                raise
+
     @unittest.skipUnless(os.utime in os.supports_fd, "test needs fd support in os.utime")
     def test_utime_with_fd(self):
         now = time.time()
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 2e5e79a..f057787 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -8917,11 +8917,16 @@
         Py_BEGIN_ALLOW_THREADS
         result = posix_fallocate(fd, offset, length);
         Py_END_ALLOW_THREADS
-    } while (result != 0 && errno == EINTR &&
-             !(async_err = PyErr_CheckSignals()));
-    if (result != 0)
-        return (!async_err) ? posix_error() : NULL;
-    Py_RETURN_NONE;
+    } while (result == EINTR && !(async_err = PyErr_CheckSignals()));
+
+    if (result == 0)
+        Py_RETURN_NONE;
+
+    if (async_err)
+        return NULL;
+
+    errno = result;
+    return posix_error();
 }
 #endif /* HAVE_POSIX_FALLOCATE) && !POSIX_FADVISE_AIX_BUG */
 
@@ -8959,11 +8964,16 @@
         Py_BEGIN_ALLOW_THREADS
         result = posix_fadvise(fd, offset, length, advice);
         Py_END_ALLOW_THREADS
-    } while (result != 0 && errno == EINTR &&
-             !(async_err = PyErr_CheckSignals()));
-    if (result != 0)
-        return (!async_err) ? posix_error() : NULL;
-    Py_RETURN_NONE;
+    } while (result == EINTR && !(async_err = PyErr_CheckSignals()));
+
+    if (result == 0)
+        Py_RETURN_NONE;
+
+    if (async_err)
+        return NULL;
+
+    errno = result;
+    return posix_error();
 }
 #endif /* HAVE_POSIX_FADVISE && !POSIX_FADVISE_AIX_BUG */