diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -976,18 +976,19 @@ static PyObject *
     r = _bufferedreader_raw_read(self, PyBytes_AS_STRING(res), n);
     LEAVE_BUFFERED(self)
     if (r == -1) {
         Py_DECREF(res);
         return NULL;
     }
     if (r == -2)
         r = 0;
-    if (n > r)
-        _PyBytes_Resize(&res, r);
+    if (_PyBytes_Resize(&res, r)) {
+        return NULL;
+    }
     return res;
 }
 
 static PyObject *
 _buffered_readinto_generic(buffered *self, Py_buffer *buffer, char readinto1)
 {
     Py_ssize_t n, written = 0, remaining;
     PyObject *res = NULL;
diff --git a/Modules/_multiprocessing/multiprocessing.c b/Modules/_multiprocessing/multiprocessing.c
--- a/Modules/_multiprocessing/multiprocessing.c
+++ b/Modules/_multiprocessing/multiprocessing.c
@@ -85,17 +85,19 @@ multiprocessing_recv(PyObject *self, PyO
     Py_BEGIN_ALLOW_THREADS
     nread = recv((SOCKET) handle, PyBytes_AS_STRING(buf), size, 0);
     Py_END_ALLOW_THREADS
 
     if (nread < 0) {
         Py_DECREF(buf);
         return PyErr_SetExcFromWindowsErr(PyExc_IOError, WSAGetLastError());
     }
-    _PyBytes_Resize(&buf, nread);
+    if (_PyBytes_Resize(&buf, nread)) {
+        return NULL;
+    }
     return buf;
 }
 
 static PyObject *
 multiprocessing_send(PyObject *self, PyObject *args)
 {
     HANDLE handle;
     Py_buffer buf;
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -2175,17 +2175,19 @@ static PyObject *
     if (count <= 0) {
         PySSL_SetError(self, count, __FILE__, __LINE__);
         goto error;
     }
 
 done:
     Py_XDECREF(sock);
     if (!group_right_1) {
-        _PyBytes_Resize(&dest, count);
+        if (_PyBytes_Resize(&dest, count)) {
+            return NULL;
+        }
         return dest;
     }
     else {
         return PyLong_FromLong(count);
     }
 
 error:
     Py_XDECREF(sock);
diff --git a/Modules/ossaudiodev.c b/Modules/ossaudiodev.c
--- a/Modules/ossaudiodev.c
+++ b/Modules/ossaudiodev.c
@@ -419,17 +419,19 @@ oss_read(oss_audio_t *self, PyObject *ar
 
     count = _Py_read(self->fd, PyBytes_AS_STRING(rv), size);
     if (count == -1) {
         Py_DECREF(rv);
         return NULL;
     }
 
     self->icount += count;
-    _PyBytes_Resize(&rv, count);
+    if (_PyBytes_Resize(&rv, count)) {
+        return NULL;
+    }
     return rv;
 }
 
 static PyObject *
 oss_write(oss_audio_t *self, PyObject *args)
 {
     Py_buffer data;
     Py_ssize_t rv;
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -7808,18 +7808,19 @@ os_read_impl(PyObject *module, int fd, P
         return NULL;
 
     n = _Py_read(fd, PyBytes_AS_STRING(buffer), length);
     if (n == -1) {
         Py_DECREF(buffer);
         return NULL;
     }
 
-    if (n != length)
-        _PyBytes_Resize(&buffer, n);
+    if (_PyBytes_Resize(&buffer, n)) {
+        return NULL;
+    }
 
     return buffer;
 }
 
 #if (defined(HAVE_SENDFILE) && (defined(__FreeBSD__) || defined(__DragonFly__) \
     || defined(__APPLE__))) || defined(HAVE_READV) || defined(HAVE_WRITEV)
 static Py_ssize_t
 iov_setup(struct iovec **iov, Py_buffer **buf, PyObject *seq, int cnt, int type)
@@ -7975,18 +7976,19 @@ os_pread_impl(PyObject *module, int fd, 
         _Py_END_SUPPRESS_IPH
         Py_END_ALLOW_THREADS
     } while (n < 0 && errno == EINTR && !(async_err = PyErr_CheckSignals()));
 
     if (n < 0) {
         Py_DECREF(buffer);
         return (!async_err) ? posix_error() : NULL;
     }
-    if (n != length)
-        _PyBytes_Resize(&buffer, n);
+    if (_PyBytes_Resize(&buffer, n)) {
+        return NULL;
+    }
     return buffer;
 }
 #endif /* HAVE_PREAD */
 
 
 /*[clinic input]
 os.write -> Py_ssize_t
 
@@ -10546,19 +10548,19 @@ os_getxattr_impl(PyObject *module, path_
         if (result < 0) {
             Py_DECREF(buffer);
             if (errno == ERANGE)
                 continue;
             path_error(path);
             return NULL;
         }
 
-        if (result != buffer_size) {
-            /* Can only shrink. */
-            _PyBytes_Resize(&buffer, result);
+        /* Can only shrink. */
+        if (_PyBytes_Resize(&buffer, result)) {
+            return NULL;
         }
         break;
     }
 
     return buffer;
 }
 
 
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -2658,17 +2658,19 @@ sock_getsockopt(PySocketSockObject *s, P
     if (buf == NULL)
         return NULL;
     res = getsockopt(s->sock_fd, level, optname,
                      (void *)PyBytes_AS_STRING(buf), &buflen);
     if (res < 0) {
         Py_DECREF(buf);
         return s->errorhandler();
     }
-    _PyBytes_Resize(&buf, buflen);
+    if (_PyBytes_Resize(&buf, buflen)) {
+        return NULL;
+    }
     return buf;
 }
 
 PyDoc_STRVAR(getsockopt_doc,
 "getsockopt(level, option[, buffersize]) -> value\n\
 \n\
 Get a socket option.  See the Unix manual for level and option.\n\
 If a nonzero buffersize argument is given, the return value is a\n\
@@ -3080,20 +3082,20 @@ sock_recv(PySocketSockObject *s, PyObjec
     /* Call the guts */
     outlen = sock_recv_guts(s, PyBytes_AS_STRING(buf), recvlen, flags);
     if (outlen < 0) {
         /* An error occurred, release the string and return an
            error. */
         Py_DECREF(buf);
         return NULL;
     }
-    if (outlen != recvlen) {
-        /* We did not read as many bytes as we anticipated, resize the
-           string if possible and be successful. */
-        _PyBytes_Resize(&buf, outlen);
+    /* We did not read as many bytes as we anticipated, resize the
+       string if possible and be successful. */
+    if (_PyBytes_Resize(&buf, outlen)) {
+        return NULL;
     }
 
     return buf;
 }
 
 PyDoc_STRVAR(recv_doc,
 "recv(buffersize[, flags]) -> data\n\
 \n\
@@ -3508,17 +3510,19 @@ err_closefds:
 
 
 static PyObject *
 makeval_recvmsg(ssize_t received, void *data)
 {
     PyObject **buf = data;
 
     if (received < PyBytes_GET_SIZE(*buf))
-        _PyBytes_Resize(buf, received);
+        if (_PyBytes_Resize(buf, received)) {
+            return NULL;
+        }
     Py_XINCREF(*buf);
     return *buf;
 }
 
 /* s.recvmsg(bufsize[, ancbufsize[, flags]]) method */
 
 static PyObject *
 sock_recvmsg(PySocketSockObject *s, PyObject *args)