trace-cmd: Add back locked record

To debug when a record is being freed and still referenced internally,
the "locked" field is added. This will flag when a record has been
freed when it should not have been.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

2 files changed, 9 insertions, 2 deletions

diff --git a/parse-events.h b/parse-events.h
index 400bc4c..bb2fe83 100644
--- a/parse-events.h
+++ b/parse-events.h
@@ -44,6 +44,7 @@ struct record {
         void                    *data;
         int                     cpu;
         int                     ref_count;
+        int                     locked;         /* Do not free, even if ref_count is zero */
         void                    *private;
 };
 
diff --git a/trace-input.c b/trace-input.c
index 9db96c7..3a70aec 100644
--- a/trace-input.c
+++ b/trace-input.c
@@ -667,6 +667,9 @@ void free_record(struct record *record)
         if (record->ref_count)
                 return;
 
+        if (record->locked)
+                die("freeing record when it is locked!");
+
         record->data = NULL;
 
         __free_record(record);
@@ -681,6 +684,7 @@ static void free_next(struct tracecmd_input *handle, int cpu)
 
         handle->cpu_data[cpu].next = NULL;
 
+        record->locked = 0;
         free_record(record);
 }
 
@@ -913,7 +917,6 @@ peek_event(struct tracecmd_input *handle, unsigned long long offset,
                 if (record && (record->offset + record->record_size) > offset)
                         break;
                 free_record(record);
-
                 free_next(handle, cpu);
         } while (record);
 
@@ -1565,6 +1568,7 @@ read_again:
         record->offset = handle->cpu_data[cpu].offset + index;
         record->missed_events = missed_events;
         record->ref_count = 2; /* will be returned and stored in page */
+        record->locked = 1;
 
         ptr += length;
 
@@ -1595,8 +1599,10 @@ tracecmd_read_data(struct tracecmd_input *handle, int cpu)
 
         record = tracecmd_peek_data(handle, cpu);
         handle->cpu_data[cpu].next = NULL;
-        if (record)
+        if (record) {
                 record->ref_count--;
+                record->locked = 0;
+        }
 
         return record;
 }