From: Steven Rostedt (VMware) <rostedt@goodmis.org>
Date: Thu, 17 Jun 2021 18:32:34 +0000 (-0400)
Subject: tracing: Do not stop recording comms if the trace file is being read
X-Git-Tag: v5.15~957^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4fdd595e4f9a1ff6d93ec702eaecae451cfc6591;p=platform%2Fkernel%2Flinux-starfive.git

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

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>
---

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index e220b37..d23a09d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2198,9 +2198,6 @@ 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];
@@ -3996,9 +3993,6 @@ 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;
@@ -4041,9 +4035,6 @@ 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();
 }