diff --git a/src/process.c b/src/process.c
index 2376d0f288d..91a5c044a8c 100644
--- a/src/process.c
+++ b/src/process.c
@@ -6128,11 +6133,11 @@ read_and_dispose_of_process_output (struct Lisp_Process *p, char *chars,
 static int
 read_process_output (Lisp_Object proc, int channel)
 {
-  ssize_t nbytes;
+  ssize_t nbytes, nnbytes = 0;
   struct Lisp_Process *p = XPROCESS (proc);
   eassert (0 <= channel && channel < FD_SETSIZE);
   struct coding_system *coding = proc_decode_coding_system[channel];
-  int carryover = p->decoding_carryover;
+  int carryover;
   ptrdiff_t readmax = clip_to_bounds (1, read_process_output_max, PTRDIFF_MAX);
   specpdl_ref count = SPECPDL_INDEX ();
   Lisp_Object odeactivate;
@@ -6141,6 +6146,9 @@ read_process_output (Lisp_Object proc, int channel)
   USE_SAFE_ALLOCA;
   chars = SAFE_ALLOCA (sizeof coding->carryover + readmax);
 
+do{
+  carryover = p->decoding_carryover;
+
   if (carryover)
     /* See the comment above.  */
     memcpy (chars, SDATA (p->decoding_buf), carryover);
@@ -6222,3 +6236,3 @@ read_process_output (Lisp_Object proc, int channel)
   /* Now set NBYTES how many bytes we must decode.  */
   nbytes += carryover;
 
@@ -6233,5 +6245,8 @@
   /* Handling the process output should not deactivate the mark.  */
   Vdeactivate_mark = odeactivate;
 
+  nnbytes += nbytes;
+ } while (nbytes >= readmax);
+
   SAFE_FREE_UNBIND_TO (count, Qnil);
-  return nbytes;
+  return nnbytes;
}