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Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 

* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  tracing: limit the number of loops the ring buffer self test can make
  tracing: have function trace select kallsyms
  tracing: disable tracing while testing ring buffer
  tracing/function-graph-tracer: trace the idle tasks
This commit is contained in:
Linus Torvalds 2009-02-19 09:14:22 -08:00
parent 83ff1af9d3 ed4a2f374d
commit f54b2fe4ae
3 changed files with 26 additions and 1 deletions
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2
kernel/trace/Kconfig
View File

@ -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.

6
kernel/trace/ftrace.c
View File

@ -2033,7 +2033,7 @@ free:
static int start_graph_tracing(void)
{
struct ftrace_ret_stack **ret_stack_list;
int ret;
int ret, cpu;
ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
sizeof(struct ftrace_ret_stack *),
@ -2042,6 +2042,10 @@ static int start_graph_tracing(void)
if (!ret_stack_list)
return -ENOMEM;
/* The cpu_boot init_task->ret_stack will never be freed */
for_each_online_cpu(cpu)
ftrace_graph_init_task(idle_task(cpu));
do {
ret = alloc_retstack_tasklist(ret_stack_list);
} while (ret == -EAGAIN);

19
kernel/trace/trace_selftest.c
View File

@ -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);