1 files changed, 12 insertions, 5 deletions

diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c
index 8ff1d55954d1..8d5ecd2bf877 100644
--- a/tools/lib/traceevent/trace-seq.c
+++ b/tools/lib/traceevent/trace-seq.c
@@ -100,7 +100,8 @@ static void expand_buffer(struct trace_seq *s)
  * @fmt: printf format string
  *
  * It returns 0 if the trace oversizes the buffer's free
- * space, 1 otherwise.
+ * space, the number of characters printed, or a negative
+ * value in case of an error.
  *
  * The tracer may use either sequence operations or its own
  * copy to user routines. To simplify formating of a trace
@@ -129,9 +130,10 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
                 goto try_again;
         }
 
-        s->len += ret;
+        if (ret > 0)
+                s->len += ret;
 
-        return 1;
+        return ret;
 }
 
 /**
@@ -139,6 +141,10 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
  * @s: trace sequence descriptor
  * @fmt: printf format string
  *
+ * It returns 0 if the trace oversizes the buffer's free
+ * space, the number of characters printed, or a negative
+ * value in case of an error.
+ * *
  * The tracer may use either sequence operations or its own
  * copy to user routines. To simplify formating of a trace
  * trace_seq_printf is used to store strings into a special
@@ -163,9 +169,10 @@ trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
                 goto try_again;
         }
 
-        s->len += ret;
+        if (ret > 0)
+                s->len += ret;
 
-        return len;
+        return ret;
 }
 
 /**