diff --git a/Process.c b/Process.c
index 07ecba15..dddd7fcd 100644
--- a/Process.c
+++ b/Process.c
@@ -335,7 +335,10 @@ void Process_outputRate(RichString* str, char* buffer, int n, double rate, int c
       largeNumberColor = CRT_colors[PROCESS];
       processMegabytesColor = CRT_colors[PROCESS];
    }
-   if (rate < ONE_K) {
+   if (rate == -1) {
+      int len = snprintf(buffer, n, "    no perm ");
+      RichString_appendn(str, CRT_colors[PROCESS_SHADOW], buffer, len);
+   } else if (rate < ONE_K) {
       int len = snprintf(buffer, n, "%7.2f B/s ", rate);
       RichString_appendn(str, processColor, buffer, len);
    } else if (rate < ONE_K * ONE_K) {
diff --git a/linux/LinuxProcess.c b/linux/LinuxProcess.c
index 17790f65..43b5e38f 100644
--- a/linux/LinuxProcess.c
+++ b/linux/LinuxProcess.c
@@ -313,7 +313,12 @@ void LinuxProcess_writeField(Process* this, RichString* str, ProcessField field)
    case CNCLWB: Process_colorNumber(str, lp->io_cancelled_write_bytes, coloring); return;
    case IO_READ_RATE:  Process_outputRate(str, buffer, n, lp->io_rate_read_bps, coloring); return;
    case IO_WRITE_RATE: Process_outputRate(str, buffer, n, lp->io_rate_write_bps, coloring); return;
-   case IO_RATE: Process_outputRate(str, buffer, n, lp->io_rate_read_bps + lp->io_rate_write_bps, coloring); return;
+   case IO_RATE: {
+      double totalRate = (lp->io_rate_read_bps != -1)
+                       ? (lp->io_rate_read_bps + lp->io_rate_write_bps)
+                       : -1;
+      Process_outputRate(str, buffer, n, totalRate, coloring); return;
+   }
    #endif
    #ifdef HAVE_OPENVZ
    case CTID: snprintf(buffer, n, "%7u ", lp->ctid); break;