tracing: Do not stop recording comms if the trace file is being read

commit 4fdd595e4f9a1ff6d93ec702eaecae451cfc6591 upstream.

A while ago, when the "trace" file was opened, tracing was stopped, and
code was added to stop recording the comms to saved_cmdlines, for mapping
of the pids to the task name.

Code has been added that only records the comm if a trace event occurred,
and there's no reason to not trace it if the trace file is opened.

Cc: stable@vger.kernel.org
Fixes: 7ffbd48d5cab2 ("tracing: Cache comms only after an event occurred")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 97df4e681bb76ec68714546386ffc3d22c01193d..b09c598065019fd69285e77a40be871eab7b3104 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2195,9 +2195,6 @@ struct saved_cmdlines_buffer {
 };
 static struct saved_cmdlines_buffer *savedcmd;
 
-/* temporary disable recording */
-static atomic_t trace_record_taskinfo_disabled __read_mostly;
-
 static inline char *get_saved_cmdlines(int idx)
 {
        return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
@@ -3683,9 +3680,6 @@ static void *s_start(struct seq_file *m, loff_t *pos)
                return ERR_PTR(-EBUSY);
 #endif
 
-       if (!iter->snapshot)
-               atomic_inc(&trace_record_taskinfo_disabled);
-
        if (*pos != iter->pos) {
                iter->ent = NULL;
                iter->cpu = 0;
@@ -3728,9 +3722,6 @@ static void s_stop(struct seq_file *m, void *p)
                return;
 #endif
 
-       if (!iter->snapshot)
-               atomic_dec(&trace_record_taskinfo_disabled);
-
        trace_access_unlock(iter->cpu_file);
        trace_event_read_unlock();
 }