提交 ed4a2f37 编写于 作者: I Ingo Molnar

Merge branch 'tip/tracing/urgent' of...

Merge branch 'tip/tracing/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/urgent
......@@ -52,6 +52,7 @@ config FUNCTION_TRACER
depends on HAVE_FUNCTION_TRACER
depends on DEBUG_KERNEL
select FRAME_POINTER
select KALLSYMS
select TRACING
select CONTEXT_SWITCH_TRACER
help
......@@ -238,6 +239,7 @@ config STACK_TRACER
depends on DEBUG_KERNEL
select FUNCTION_TRACER
select STACKTRACE
select KALLSYMS
help
This special tracer records the maximum stack footprint of the
kernel and displays it in debugfs/tracing/stack_trace.
......
......@@ -23,10 +23,20 @@ static int trace_test_buffer_cpu(struct trace_array *tr, int cpu)
{
struct ring_buffer_event *event;
struct trace_entry *entry;
unsigned int loops = 0;
while ((event = ring_buffer_consume(tr->buffer, cpu, NULL))) {
entry = ring_buffer_event_data(event);
/*
* The ring buffer is a size of trace_buf_size, if
* we loop more than the size, there's something wrong
* with the ring buffer.
*/
if (loops++ > trace_buf_size) {
printk(KERN_CONT ".. bad ring buffer ");
goto failed;
}
if (!trace_valid_entry(entry)) {
printk(KERN_CONT ".. invalid entry %d ",
entry->type);
......@@ -57,11 +67,20 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count)
cnt = ring_buffer_entries(tr->buffer);
/*
* The trace_test_buffer_cpu runs a while loop to consume all data.
* If the calling tracer is broken, and is constantly filling
* the buffer, this will run forever, and hard lock the box.
* We disable the ring buffer while we do this test to prevent
* a hard lock up.
*/
tracing_off();
for_each_possible_cpu(cpu) {
ret = trace_test_buffer_cpu(tr, cpu);
if (ret)
break;
}
tracing_on();
__raw_spin_unlock(&ftrace_max_lock);
local_irq_restore(flags);
......
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