Commit 8dd33bcb authored Sep 18, 2017 by Bo Yan Committed by Steven Rostedt (VMware) Sep 19, 2017

tracing: Erase irqsoff trace with empty write

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.

Link: http://lkml.kernel.org/r/1505754215-29411-1-git-send-email-byan@nvidia.com



Cc: <mingo@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 4acd4d00 ("tracing: give easy way to clear trace buffer")
Signed-off-by: Bo Yan <byan@nvidia.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent 170b3b10

kernel/trace/trace.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -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 *trace_buf = &tr->trace_buffer;

		#ifdef CONFIG_TRACER_MAX_TRACE
		if (tr->current_trace->print_max)
		trace_buf = &tr->max_buffer;
		#endif

		if (cpu == RING_BUFFER_ALL_CPUS)
		tracing_reset_online_cpus(&tr->trace_buffer);
		tracing_reset_online_cpus(trace_buf);
		else
		tracing_reset(&tr->trace_buffer, cpu);
		tracing_reset(trace_buf, cpu);
		}

		if (file->f_mode & FMODE_READ) {

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