From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20170920133012.763216723@goodmis.org> Date: Wed, 20 Sep 2017 09:29:39 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Linus Torvalds , Ingo Molnar , Andrew Morton , , stable@vger.kernel.org, Bo Yan Subject: [PATCH 1/3] tracing: Erase irqsoff trace with empty write References: <20170920132938.098873640@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0001-tracing-Erase-irqsoff-trace-with-empty-write.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: From: Bo Yan 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: Cc: stable@vger.kernel.org Fixes: 4acd4d00f ("tracing: give easy way to clear trace buffer") Signed-off-by: Bo Yan Signed-off-by: Steven Rostedt (VMware) --- 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..a7fb136da891 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 *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) { -- 2.13.2