diff mbox series

[v4,10/15] tracing: Stop the tracing while changing the ring buffer subbuf size

Message ID 20231215175546.125060181@goodmis.org (mailing list archive)
State Superseded
Headers show
Series ring-buffer/tracing: Allow ring buffer to have bigger sub buffers | expand

Commit Message

Steven Rostedt Dec. 15, 2023, 5:55 p.m. UTC 
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

Because the main buffer and the snapshot buffer need to be the same for
some tracers, otherwise it will fail and disable all tracing, the tracers
need to be stopped while updating the sub buffer sizes so that the tracers
see the main and snapshot buffers with the same sub buffer size.

Fixes: TBD ("ring-buffer: Add interface for configuring trace sub buffer size")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 836514e566c7..b4626c9223a5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -9419,13 +9419,16 @@  buffer_order_write(struct file *filp, const char __user *ubuf,
 	if (val < 0 || val > 7)
 		return -EINVAL;
 
+	/* Do not allow tracing while changing the order of the ring buffer */
+	tracing_stop_tr(tr);
+
 	old_order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
 	if (old_order == val)
-		return 0;
+		goto out;
 
 	ret = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, val);
 	if (ret)
-		return 0;
+		goto out;
 
 #ifdef CONFIG_TRACER_MAX_TRACE
 
@@ -9452,11 +9455,15 @@  buffer_order_write(struct file *filp, const char __user *ubuf,
 			 */
 			tracing_disabled = 1;
 		}
-		return ret;
+		goto out;
 	}
  out_max:
 #endif
 	(*ppos)++;
+ out:
+	if (ret)
+		cnt = ret;
+	tracing_start_tr(tr);
 	return cnt;
 }