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Groups > linux.kernel > #1730468

[PATCH] tracing: erase irqsoff trace with empty write

From Bo Yan <byan@nvidia.com>
Newsgroups linux.kernel
Subject [PATCH] tracing: erase irqsoff trace with empty write
Date 2017-09-11 20:20 +0200
Message-ID <uoBtn-6V3-5@gated-at.bofh.it> (permalink)
Organization linux.* mail to news gateway

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One convenient way to erase trace is "echo > trace". However, this
is currently broken if the current tracer is irqsoff tracer. This
is because irqsoff tracer use max_buffer as the default trace
buffer.

Set the max_buffer as the one to be cleared when it's the trace
buffer currently in use.

Signed-off-by: Bo Yan <byan@nvidia.com>
---
 kernel/trace/trace.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 5360b7aec57a..1f91bdd9365b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4020,11 +4020,17 @@ static int tracing_open(struct inode *inode, struct file *file)
 	/* If this file was open for write, then erase contents */
 	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 		int cpu = tracing_get_cpu(inode);
+		struct trace_buffer *tr_buf = &tr->trace_buffer;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+		if (tr->current_trace->print_max)
+			tr_buf = &tr->max_buffer;
+#endif
 
 		if (cpu == RING_BUFFER_ALL_CPUS)
-			tracing_reset_online_cpus(&tr->trace_buffer);
+			tracing_reset_online_cpus(tr_buf);
 		else
-			tracing_reset(&tr->trace_buffer, cpu);
+			tracing_reset(tr_buf, cpu);
 	}
 
 	if (file->f_mode & FMODE_READ) {
-- 
2.7.4

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[PATCH] tracing: erase irqsoff trace with empty write Bo Yan <byan@nvidia.com> - 2017-09-11 20:20 +0200
  Re: [PATCH] tracing: erase irqsoff trace with empty write Steven Rostedt <rostedt@goodmis.org> - 2017-09-18 16:40 +0200
    Re: [PATCH] tracing: erase irqsoff trace with empty write Bo Yan <byan@nvidia.com> - 2017-09-19 19:50 +0200
      Re: [PATCH] tracing: erase irqsoff trace with empty write Steven Rostedt <rostedt@goodmis.org> - 2017-09-19 19:50 +0200

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