/* Include in trace.c */
+#include <linux/stringify.h>
#include <linux/kthread.h>
#include <linux/delay.h>
+#include <linux/slab.h>
static inline int trace_valid_entry(struct trace_entry *entry)
{
case TRACE_BRANCH:
case TRACE_GRAPH_ENT:
case TRACE_GRAPH_RET:
+ case TRACE_KSYM:
return 1;
}
return 0;
{
struct ring_buffer_event *event;
struct trace_entry *entry;
+ unsigned int loops = 0;
- while ((event = ring_buffer_consume(tr->buffer, cpu, NULL))) {
+ while ((event = ring_buffer_consume(tr->buffer, cpu, NULL, 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);
/* Don't allow flipping of max traces now */
local_irq_save(flags);
- __raw_spin_lock(&ftrace_max_lock);
+ arch_spin_lock(&ftrace_max_lock);
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;
}
- __raw_spin_unlock(&ftrace_max_lock);
+ tracing_on();
+ arch_spin_unlock(&ftrace_max_lock);
local_irq_restore(flags);
if (count)
#ifdef CONFIG_DYNAMIC_FTRACE
-#define __STR(x) #x
-#define STR(x) __STR(x)
-
/* Test dynamic code modification and ftrace filters */
int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
struct trace_array *tr,
func();
/*
- * Some archs *cough*PowerPC*cough* add charachters to the
+ * Some archs *cough*PowerPC*cough* add characters to the
* start of the function names. We simply put a '*' to
- * accomodate them.
+ * accommodate them.
*/
- func_name = "*" STR(DYN_FTRACE_TEST_NAME);
+ func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
/* filter only on our function */
ftrace_set_filter(func_name, strlen(func_name), 1);
#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
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+/* Maximum number of functions to trace before diagnosing a hang */
+#define GRAPH_MAX_FUNC_TEST 100000000
+
+static void
+__ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode);
+static unsigned int graph_hang_thresh;
+
+/* Wrap the real function entry probe to avoid possible hanging */
+static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace)
+{
+ /* This is harmlessly racy, we want to approximately detect a hang */
+ if (unlikely(++graph_hang_thresh > GRAPH_MAX_FUNC_TEST)) {
+ ftrace_graph_stop();
+ printk(KERN_WARNING "BUG: Function graph tracer hang!\n");
+ if (ftrace_dump_on_oops)
+ __ftrace_dump(false, DUMP_ALL);
+ return 0;
+ }
+
+ return trace_graph_entry(trace);
+}
+
/*
* Pretty much the same than for the function tracer from which the selftest
* has been borrowed.
int ret;
unsigned long count;
- ret = tracer_init(trace, tr);
+ /*
+ * Simulate the init() callback but we attach a watchdog callback
+ * to detect and recover from possible hangs
+ */
+ tracing_reset_online_cpus(tr);
+ set_graph_array(tr);
+ ret = register_ftrace_graph(&trace_graph_return,
+ &trace_graph_entry_watchdog);
if (ret) {
warn_failed_init_tracer(trace, ret);
goto out;
}
+ tracing_start_cmdline_record();
/* Sleep for a 1/10 of a second */
msleep(100);
+ /* Have we just recovered from a hang? */
+ if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) {
+ tracing_selftest_disabled = true;
+ ret = -1;
+ goto out;
+ }
+
tracing_stop();
/* check the trace buffer */
local_irq_disable();
udelay(100);
local_irq_enable();
+
+ /*
+ * Stop the tracer to avoid a warning subsequent
+ * to buffer flipping failure because tracing_stop()
+ * disables the tr and max buffers, making flipping impossible
+ * in case of parallels max irqs off latencies.
+ */
+ trace->stop(tr);
/* stop the tracing. */
tracing_stop();
/* check both trace buffers */
preempt_disable();
udelay(100);
preempt_enable();
+
+ /*
+ * Stop the tracer to avoid a warning subsequent
+ * to buffer flipping failure because tracing_stop()
+ * disables the tr and max buffers, making flipping impossible
+ * in case of parallels max preempt off latencies.
+ */
+ trace->stop(tr);
/* stop the tracing. */
tracing_stop();
/* check both trace buffers */
ret = tracer_init(trace, tr);
if (ret) {
warn_failed_init_tracer(trace, ret);
- goto out;
+ goto out_no_start;
}
/* reset the max latency */
/* reverse the order of preempt vs irqs */
local_irq_enable();
+ /*
+ * Stop the tracer to avoid a warning subsequent
+ * to buffer flipping failure because tracing_stop()
+ * disables the tr and max buffers, making flipping impossible
+ * in case of parallels max irqs/preempt off latencies.
+ */
+ trace->stop(tr);
/* stop the tracing. */
tracing_stop();
/* check both trace buffers */
ret = trace_test_buffer(tr, NULL);
- if (ret) {
- tracing_start();
+ if (ret)
goto out;
- }
ret = trace_test_buffer(&max_tr, &count);
- if (ret) {
- tracing_start();
+ if (ret)
goto out;
- }
if (!ret && !count) {
printk(KERN_CONT ".. no entries found ..");
ret = -1;
- tracing_start();
goto out;
}
/* do the test by disabling interrupts first this time */
tracing_max_latency = 0;
tracing_start();
+ trace->start(tr);
+
preempt_disable();
local_irq_disable();
udelay(100);
/* reverse the order of preempt vs irqs */
local_irq_enable();
+ trace->stop(tr);
/* stop the tracing. */
tracing_stop();
/* check both trace buffers */
goto out;
}
- out:
- trace->reset(tr);
+out:
tracing_start();
+out_no_start:
+ trace->reset(tr);
tracing_max_latency = save_max;
return ret;
ret = tracer_init(trace, tr);
if (ret) {
warn_failed_init_tracer(trace, ret);
- return 0;
+ return ret;
}
/* Sleep for a 1/10 of a second */
trace->reset(tr);
tracing_start();
+ if (!ret && !count) {
+ printk(KERN_CONT ".. no entries found ..");
+ ret = -1;
+ }
+
return ret;
}
#endif /* CONFIG_SYSPROF_TRACER */
trace->reset(tr);
tracing_start();
+ if (!ret && !count) {
+ printk(KERN_CONT ".. no entries found ..");
+ ret = -1;
+ }
+
return ret;
}
#endif /* CONFIG_BRANCH_TRACER */
+
+#ifdef CONFIG_KSYM_TRACER
+static int ksym_selftest_dummy;
+
+int
+trace_selftest_startup_ksym(struct tracer *trace, struct trace_array *tr)
+{
+ unsigned long count;
+ int ret;
+
+ /* start the tracing */
+ ret = tracer_init(trace, tr);
+ if (ret) {
+ warn_failed_init_tracer(trace, ret);
+ return ret;
+ }
+
+ ksym_selftest_dummy = 0;
+ /* Register the read-write tracing request */
+
+ ret = process_new_ksym_entry("ksym_selftest_dummy",
+ HW_BREAKPOINT_R | HW_BREAKPOINT_W,
+ (unsigned long)(&ksym_selftest_dummy));
+
+ if (ret < 0) {
+ printk(KERN_CONT "ksym_trace read-write startup test failed\n");
+ goto ret_path;
+ }
+ /* Perform a read and a write operation over the dummy variable to
+ * trigger the tracer
+ */
+ if (ksym_selftest_dummy == 0)
+ ksym_selftest_dummy++;
+
+ /* stop the tracing. */
+ tracing_stop();
+ /* check the trace buffer */
+ ret = trace_test_buffer(tr, &count);
+ trace->reset(tr);
+ tracing_start();
+
+ /* read & write operations - one each is performed on the dummy variable
+ * triggering two entries in the trace buffer
+ */
+ if (!ret && count != 2) {
+ printk(KERN_CONT "Ksym tracer startup test failed");
+ ret = -1;
+ }
+
+ret_path:
+ return ret;
+}
+#endif /* CONFIG_KSYM_TRACER */
+
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