From b8de7bd168fa54d059b16d3057b2f8a32cc5bdc3 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 31 Aug 2009 22:32:27 -0400 Subject: [PATCH] tracing: disable update max tracer while reading trace When reading the tracer from the trace file, updating the max latency may corrupt the output. This patch disables the tracing of the max latency while reading the trace file. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index df2c9f730ac6..e521f1e8f2bb 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -263,6 +263,9 @@ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME | TRACE_ITER_GRAPH_TIME; +static int trace_stop_count; +static DEFINE_SPINLOCK(tracing_start_lock); + /** * trace_wake_up - wake up tasks waiting for trace input * @@ -442,6 +445,9 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) { struct ring_buffer *buf = tr->buffer; + if (trace_stop_count) + return; + WARN_ON_ONCE(!irqs_disabled()); __raw_spin_lock(&ftrace_max_lock); @@ -469,6 +475,9 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) { int ret; + if (trace_stop_count) + return; + WARN_ON_ONCE(!irqs_disabled()); __raw_spin_lock(&ftrace_max_lock); @@ -685,9 +694,6 @@ static void trace_init_cmdlines(void) cmdline_idx = 0; } -static int trace_stop_count; -static DEFINE_SPINLOCK(tracing_start_lock); - /** * ftrace_off_permanent - disable all ftrace code permanently * -- 2.20.1