From: Bo Yan Date: Mon, 18 Sep 2017 17:03:35 +0000 (-0700) Subject: tracing: Erase irqsoff trace with empty write X-Git-Tag: v4.13.5~87 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=422f1a31123dd1b75a1964acabb63c23566ced16;p=users%2Fdwmw2%2Flinux.git tracing: Erase irqsoff trace with empty write commit 8dd33bcb7050dd6f8c1432732f930932c9d3a33e upstream. 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: Fixes: 4acd4d00f ("tracing: give easy way to clear trace buffer") Signed-off-by: Bo Yan Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 46359c14fc181..27a723480b135 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4017,11 +4017,17 @@ 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) {