forked from Minki/linux
77a2b37d22
This patch adds a startup self test on dynamic code modification and filters. The test filters on a specific function, makes sure that no other function is traced, exectutes the function, then makes sure that the function is traced. This patch also fixes a slight bug with the ftrace selftest, where tracer_enabled was not being set. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
526 lines
11 KiB
C
526 lines
11 KiB
C
/* Include in trace.c */
|
|
|
|
#include <linux/kthread.h>
|
|
#include <linux/delay.h>
|
|
|
|
static inline int trace_valid_entry(struct trace_entry *entry)
|
|
{
|
|
switch (entry->type) {
|
|
case TRACE_FN:
|
|
case TRACE_CTX:
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
trace_test_buffer_cpu(struct trace_array *tr, struct trace_array_cpu *data)
|
|
{
|
|
struct trace_entry *entries;
|
|
struct page *page;
|
|
int idx = 0;
|
|
int i;
|
|
|
|
BUG_ON(list_empty(&data->trace_pages));
|
|
page = list_entry(data->trace_pages.next, struct page, lru);
|
|
entries = page_address(page);
|
|
|
|
if (head_page(data) != entries)
|
|
goto failed;
|
|
|
|
/*
|
|
* The starting trace buffer always has valid elements,
|
|
* if any element exists.
|
|
*/
|
|
entries = head_page(data);
|
|
|
|
for (i = 0; i < tr->entries; i++) {
|
|
|
|
if (i < data->trace_idx && !trace_valid_entry(&entries[idx])) {
|
|
printk(KERN_CONT ".. invalid entry %d ",
|
|
entries[idx].type);
|
|
goto failed;
|
|
}
|
|
|
|
idx++;
|
|
if (idx >= ENTRIES_PER_PAGE) {
|
|
page = virt_to_page(entries);
|
|
if (page->lru.next == &data->trace_pages) {
|
|
if (i != tr->entries - 1) {
|
|
printk(KERN_CONT ".. entries buffer mismatch");
|
|
goto failed;
|
|
}
|
|
} else {
|
|
page = list_entry(page->lru.next, struct page, lru);
|
|
entries = page_address(page);
|
|
}
|
|
idx = 0;
|
|
}
|
|
}
|
|
|
|
page = virt_to_page(entries);
|
|
if (page->lru.next != &data->trace_pages) {
|
|
printk(KERN_CONT ".. too many entries");
|
|
goto failed;
|
|
}
|
|
|
|
return 0;
|
|
|
|
failed:
|
|
printk(KERN_CONT ".. corrupted trace buffer .. ");
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* Test the trace buffer to see if all the elements
|
|
* are still sane.
|
|
*/
|
|
static int trace_test_buffer(struct trace_array *tr, unsigned long *count)
|
|
{
|
|
unsigned long cnt = 0;
|
|
int cpu;
|
|
int ret = 0;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
if (!head_page(tr->data[cpu]))
|
|
continue;
|
|
|
|
cnt += tr->data[cpu]->trace_idx;
|
|
|
|
ret = trace_test_buffer_cpu(tr, tr->data[cpu]);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
if (count)
|
|
*count = cnt;
|
|
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_FTRACE
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
|
|
#define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
|
|
#define __STR(x) #x
|
|
#define STR(x) __STR(x)
|
|
static int DYN_FTRACE_TEST_NAME(void)
|
|
{
|
|
/* used to call mcount */
|
|
return 0;
|
|
}
|
|
|
|
/* Test dynamic code modification and ftrace filters */
|
|
int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
|
|
struct trace_array *tr,
|
|
int (*func)(void))
|
|
{
|
|
unsigned long count;
|
|
int ret;
|
|
int save_ftrace_enabled = ftrace_enabled;
|
|
int save_tracer_enabled = tracer_enabled;
|
|
|
|
/* The ftrace test PASSED */
|
|
printk(KERN_CONT "PASSED\n");
|
|
pr_info("Testing dynamic ftrace: ");
|
|
|
|
/* enable tracing, and record the filter function */
|
|
ftrace_enabled = 1;
|
|
tracer_enabled = 1;
|
|
|
|
/* passed in by parameter to fool gcc from optimizing */
|
|
func();
|
|
|
|
/* update the records */
|
|
ret = ftrace_force_update();
|
|
if (ret) {
|
|
printk(KERN_CONT ".. ftraced failed .. ");
|
|
return ret;
|
|
}
|
|
|
|
/* filter only on our function */
|
|
ftrace_set_filter(STR(DYN_FTRACE_TEST_NAME),
|
|
sizeof(STR(DYN_FTRACE_TEST_NAME)), 1);
|
|
|
|
/* enable tracing */
|
|
tr->ctrl = 1;
|
|
trace->init(tr);
|
|
/* Sleep for a 1/10 of a second */
|
|
msleep(100);
|
|
|
|
/* we should have nothing in the buffer */
|
|
ret = trace_test_buffer(tr, &count);
|
|
if (ret)
|
|
goto out;
|
|
|
|
if (count) {
|
|
ret = -1;
|
|
printk(KERN_CONT ".. filter did not filter .. ");
|
|
goto out;
|
|
}
|
|
|
|
/* call our function again */
|
|
func();
|
|
|
|
/* sleep again */
|
|
msleep(100);
|
|
|
|
/* stop the tracing. */
|
|
tr->ctrl = 0;
|
|
trace->ctrl_update(tr);
|
|
ftrace_enabled = 0;
|
|
|
|
/* check the trace buffer */
|
|
ret = trace_test_buffer(tr, &count);
|
|
trace->reset(tr);
|
|
|
|
/* we should only have one item */
|
|
if (!ret && count != 1) {
|
|
printk(KERN_CONT ".. filter failed ..");
|
|
ret = -1;
|
|
goto out;
|
|
}
|
|
out:
|
|
ftrace_enabled = save_ftrace_enabled;
|
|
tracer_enabled = save_tracer_enabled;
|
|
|
|
/* Enable tracing on all functions again */
|
|
ftrace_set_filter(NULL, 0, 1);
|
|
|
|
return ret;
|
|
}
|
|
#else
|
|
# define trace_selftest_startup_dynamic_tracing(trace, tr, func) ({ 0; })
|
|
#endif /* CONFIG_DYNAMIC_FTRACE */
|
|
/*
|
|
* Simple verification test of ftrace function tracer.
|
|
* Enable ftrace, sleep 1/10 second, and then read the trace
|
|
* buffer to see if all is in order.
|
|
*/
|
|
int
|
|
trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
|
|
{
|
|
unsigned long count;
|
|
int ret;
|
|
int save_ftrace_enabled = ftrace_enabled;
|
|
int save_tracer_enabled = tracer_enabled;
|
|
|
|
/* make sure msleep has been recorded */
|
|
msleep(1);
|
|
|
|
/* force the recorded functions to be traced */
|
|
ret = ftrace_force_update();
|
|
if (ret) {
|
|
printk(KERN_CONT ".. ftraced failed .. ");
|
|
return ret;
|
|
}
|
|
|
|
/* start the tracing */
|
|
ftrace_enabled = 1;
|
|
tracer_enabled = 1;
|
|
|
|
tr->ctrl = 1;
|
|
trace->init(tr);
|
|
/* Sleep for a 1/10 of a second */
|
|
msleep(100);
|
|
/* stop the tracing. */
|
|
tr->ctrl = 0;
|
|
trace->ctrl_update(tr);
|
|
ftrace_enabled = 0;
|
|
|
|
/* check the trace buffer */
|
|
ret = trace_test_buffer(tr, &count);
|
|
trace->reset(tr);
|
|
|
|
if (!ret && !count) {
|
|
printk(KERN_CONT ".. no entries found ..");
|
|
ret = -1;
|
|
goto out;
|
|
}
|
|
|
|
ret = trace_selftest_startup_dynamic_tracing(trace, tr,
|
|
DYN_FTRACE_TEST_NAME);
|
|
|
|
out:
|
|
ftrace_enabled = save_ftrace_enabled;
|
|
tracer_enabled = save_tracer_enabled;
|
|
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_FTRACE */
|
|
|
|
#ifdef CONFIG_IRQSOFF_TRACER
|
|
int
|
|
trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
|
|
{
|
|
unsigned long save_max = tracing_max_latency;
|
|
unsigned long count;
|
|
int ret;
|
|
|
|
/* start the tracing */
|
|
tr->ctrl = 1;
|
|
trace->init(tr);
|
|
/* reset the max latency */
|
|
tracing_max_latency = 0;
|
|
/* disable interrupts for a bit */
|
|
local_irq_disable();
|
|
udelay(100);
|
|
local_irq_enable();
|
|
/* stop the tracing. */
|
|
tr->ctrl = 0;
|
|
trace->ctrl_update(tr);
|
|
/* check both trace buffers */
|
|
ret = trace_test_buffer(tr, NULL);
|
|
if (!ret)
|
|
ret = trace_test_buffer(&max_tr, &count);
|
|
trace->reset(tr);
|
|
|
|
if (!ret && !count) {
|
|
printk(KERN_CONT ".. no entries found ..");
|
|
ret = -1;
|
|
}
|
|
|
|
tracing_max_latency = save_max;
|
|
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_IRQSOFF_TRACER */
|
|
|
|
#ifdef CONFIG_PREEMPT_TRACER
|
|
int
|
|
trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
|
|
{
|
|
unsigned long save_max = tracing_max_latency;
|
|
unsigned long count;
|
|
int ret;
|
|
|
|
/* start the tracing */
|
|
tr->ctrl = 1;
|
|
trace->init(tr);
|
|
/* reset the max latency */
|
|
tracing_max_latency = 0;
|
|
/* disable preemption for a bit */
|
|
preempt_disable();
|
|
udelay(100);
|
|
preempt_enable();
|
|
/* stop the tracing. */
|
|
tr->ctrl = 0;
|
|
trace->ctrl_update(tr);
|
|
/* check both trace buffers */
|
|
ret = trace_test_buffer(tr, NULL);
|
|
if (!ret)
|
|
ret = trace_test_buffer(&max_tr, &count);
|
|
trace->reset(tr);
|
|
|
|
if (!ret && !count) {
|
|
printk(KERN_CONT ".. no entries found ..");
|
|
ret = -1;
|
|
}
|
|
|
|
tracing_max_latency = save_max;
|
|
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_PREEMPT_TRACER */
|
|
|
|
#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
|
|
int
|
|
trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr)
|
|
{
|
|
unsigned long save_max = tracing_max_latency;
|
|
unsigned long count;
|
|
int ret;
|
|
|
|
/* start the tracing */
|
|
tr->ctrl = 1;
|
|
trace->init(tr);
|
|
|
|
/* reset the max latency */
|
|
tracing_max_latency = 0;
|
|
|
|
/* disable preemption and interrupts for a bit */
|
|
preempt_disable();
|
|
local_irq_disable();
|
|
udelay(100);
|
|
preempt_enable();
|
|
/* reverse the order of preempt vs irqs */
|
|
local_irq_enable();
|
|
|
|
/* stop the tracing. */
|
|
tr->ctrl = 0;
|
|
trace->ctrl_update(tr);
|
|
/* check both trace buffers */
|
|
ret = trace_test_buffer(tr, NULL);
|
|
if (ret)
|
|
goto out;
|
|
|
|
ret = trace_test_buffer(&max_tr, &count);
|
|
if (ret)
|
|
goto out;
|
|
|
|
if (!ret && !count) {
|
|
printk(KERN_CONT ".. no entries found ..");
|
|
ret = -1;
|
|
goto out;
|
|
}
|
|
|
|
/* do the test by disabling interrupts first this time */
|
|
tracing_max_latency = 0;
|
|
tr->ctrl = 1;
|
|
trace->ctrl_update(tr);
|
|
preempt_disable();
|
|
local_irq_disable();
|
|
udelay(100);
|
|
preempt_enable();
|
|
/* reverse the order of preempt vs irqs */
|
|
local_irq_enable();
|
|
|
|
/* stop the tracing. */
|
|
tr->ctrl = 0;
|
|
trace->ctrl_update(tr);
|
|
/* check both trace buffers */
|
|
ret = trace_test_buffer(tr, NULL);
|
|
if (ret)
|
|
goto out;
|
|
|
|
ret = trace_test_buffer(&max_tr, &count);
|
|
|
|
if (!ret && !count) {
|
|
printk(KERN_CONT ".. no entries found ..");
|
|
ret = -1;
|
|
goto out;
|
|
}
|
|
|
|
out:
|
|
trace->reset(tr);
|
|
tracing_max_latency = save_max;
|
|
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */
|
|
|
|
#ifdef CONFIG_SCHED_TRACER
|
|
static int trace_wakeup_test_thread(void *data)
|
|
{
|
|
struct completion *x = data;
|
|
|
|
/* Make this a RT thread, doesn't need to be too high */
|
|
|
|
rt_mutex_setprio(current, MAX_RT_PRIO - 5);
|
|
|
|
/* Make it know we have a new prio */
|
|
complete(x);
|
|
|
|
/* now go to sleep and let the test wake us up */
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
schedule();
|
|
|
|
/* we are awake, now wait to disappear */
|
|
while (!kthread_should_stop()) {
|
|
/*
|
|
* This is an RT task, do short sleeps to let
|
|
* others run.
|
|
*/
|
|
msleep(100);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
|
|
{
|
|
unsigned long save_max = tracing_max_latency;
|
|
struct task_struct *p;
|
|
struct completion isrt;
|
|
unsigned long count;
|
|
int ret;
|
|
|
|
init_completion(&isrt);
|
|
|
|
/* create a high prio thread */
|
|
p = kthread_run(trace_wakeup_test_thread, &isrt, "ftrace-test");
|
|
if (IS_ERR(p)) {
|
|
printk(KERN_CONT "Failed to create ftrace wakeup test thread ");
|
|
return -1;
|
|
}
|
|
|
|
/* make sure the thread is running at an RT prio */
|
|
wait_for_completion(&isrt);
|
|
|
|
/* start the tracing */
|
|
tr->ctrl = 1;
|
|
trace->init(tr);
|
|
/* reset the max latency */
|
|
tracing_max_latency = 0;
|
|
|
|
/* sleep to let the RT thread sleep too */
|
|
msleep(100);
|
|
|
|
/*
|
|
* Yes this is slightly racy. It is possible that for some
|
|
* strange reason that the RT thread we created, did not
|
|
* call schedule for 100ms after doing the completion,
|
|
* and we do a wakeup on a task that already is awake.
|
|
* But that is extremely unlikely, and the worst thing that
|
|
* happens in such a case, is that we disable tracing.
|
|
* Honestly, if this race does happen something is horrible
|
|
* wrong with the system.
|
|
*/
|
|
|
|
wake_up_process(p);
|
|
|
|
/* stop the tracing. */
|
|
tr->ctrl = 0;
|
|
trace->ctrl_update(tr);
|
|
/* check both trace buffers */
|
|
ret = trace_test_buffer(tr, NULL);
|
|
if (!ret)
|
|
ret = trace_test_buffer(&max_tr, &count);
|
|
|
|
|
|
trace->reset(tr);
|
|
|
|
tracing_max_latency = save_max;
|
|
|
|
/* kill the thread */
|
|
kthread_stop(p);
|
|
|
|
if (!ret && !count) {
|
|
printk(KERN_CONT ".. no entries found ..");
|
|
ret = -1;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_SCHED_TRACER */
|
|
|
|
#ifdef CONFIG_CONTEXT_SWITCH_TRACER
|
|
int
|
|
trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr)
|
|
{
|
|
unsigned long count;
|
|
int ret;
|
|
|
|
/* start the tracing */
|
|
tr->ctrl = 1;
|
|
trace->init(tr);
|
|
/* Sleep for a 1/10 of a second */
|
|
msleep(100);
|
|
/* stop the tracing. */
|
|
tr->ctrl = 0;
|
|
trace->ctrl_update(tr);
|
|
/* check the trace buffer */
|
|
ret = trace_test_buffer(tr, &count);
|
|
trace->reset(tr);
|
|
|
|
if (!ret && !count) {
|
|
printk(KERN_CONT ".. no entries found ..");
|
|
ret = -1;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_CONTEXT_SWITCH_TRACER */
|