1 files changed, 161 insertions, 27 deletions

diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 88c8eb70f54a..08f4eb2763d1 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -1,5 +1,6 @@
 /* Include in trace.c */
 
+#include <linux/stringify.h>
 #include <linux/kthread.h>
 #include <linux/delay.h>
 
@@ -9,11 +10,12 @@ static inline int trace_valid_entry(struct trace_entry *entry)
         case TRACE_FN:
         case TRACE_CTX:
         case TRACE_WAKE:
-        case TRACE_CONT:
         case TRACE_STACK:
         case TRACE_PRINT:
         case TRACE_SPECIAL:
         case TRACE_BRANCH:
+        case TRACE_GRAPH_ENT:
+        case TRACE_GRAPH_RET:
                 return 1;
         }
         return 0;
@@ -23,10 +25,20 @@ 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 +69,20 @@ 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);
 
@@ -80,9 +101,6 @@ static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret)
 
 #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,
@@ -106,17 +124,17 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
         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);
 
         /* enable tracing */
-        ret = trace->init(tr);
+        ret = tracer_init(trace, tr);
         if (ret) {
                 warn_failed_init_tracer(trace, ret);
                 goto out;
@@ -190,7 +208,7 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
         ftrace_enabled = 1;
         tracer_enabled = 1;
 
-        ret = trace->init(tr);
+        ret = tracer_init(trace, tr);
         if (ret) {
                 warn_failed_init_tracer(trace, ret);
                 goto out;
@@ -228,6 +246,90 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
 }
 #endif /* CONFIG_FUNCTION_TRACER */
 
+
+#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);
+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);
+                return 0;
+        }
+
+        return trace_graph_entry(trace);
+}
+
+/*
+ * Pretty much the same than for the function tracer from which the selftest
+ * has been borrowed.
+ */
+int
+trace_selftest_startup_function_graph(struct tracer *trace,
+                                        struct trace_array *tr)
+{
+        int ret;
+        unsigned long count;
+
+        /*
+         * Simulate the init() callback but we attach a watchdog callback
+         * to detect and recover from possible hangs
+         */
+        tracing_reset_online_cpus(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 */
+        ret = trace_test_buffer(tr, &count);
+
+        trace->reset(tr);
+        tracing_start();
+
+        if (!ret && !count) {
+                printk(KERN_CONT ".. no entries found ..");
+                ret = -1;
+                goto out;
+        }
+
+        /* Don't test dynamic tracing, the function tracer already did */
+
+out:
+        /* Stop it if we failed */
+        if (ret)
+                ftrace_graph_stop();
+
+        return ret;
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+
 #ifdef CONFIG_IRQSOFF_TRACER
 int
 trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
@@ -237,7 +339,7 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
         int ret;
 
         /* start the tracing */
-        ret = trace->init(tr);
+        ret = tracer_init(trace, tr);
         if (ret) {
                 warn_failed_init_tracer(trace, ret);
                 return ret;
@@ -249,6 +351,14 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
         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 */
@@ -291,7 +401,7 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
         }
 
         /* start the tracing */
-        ret = trace->init(tr);
+        ret = tracer_init(trace, tr);
         if (ret) {
                 warn_failed_init_tracer(trace, ret);
                 return ret;
@@ -303,6 +413,14 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
         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 */
@@ -345,10 +463,10 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *
         }
 
         /* start the tracing */
-        ret = trace->init(tr);
+        ret = tracer_init(trace, tr);
         if (ret) {
                 warn_failed_init_tracer(trace, ret);
-                goto out;
+                goto out_no_start;
         }
 
         /* reset the max latency */
@@ -362,31 +480,35 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *
         /* 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);
@@ -394,6 +516,7 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *
         /* reverse the order of preempt vs irqs */
         local_irq_enable();
 
+        trace->stop(tr);
         /* stop the tracing. */
         tracing_stop();
         /* check both trace buffers */
@@ -409,9 +532,10 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *
                 goto out;
         }
 
- out:
-        trace->reset(tr);
+out:
         tracing_start();
+out_no_start:
+        trace->reset(tr);
         tracing_max_latency = save_max;
 
         return ret;
@@ -477,7 +601,7 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
         wait_for_completion(&isrt);
 
         /* start the tracing */
-        ret = trace->init(tr);
+        ret = tracer_init(trace, tr);
         if (ret) {
                 warn_failed_init_tracer(trace, ret);
                 return ret;
@@ -538,7 +662,7 @@ trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr
         int ret;
 
         /* start the tracing */
-        ret = trace->init(tr);
+        ret = tracer_init(trace, tr);
         if (ret) {
                 warn_failed_init_tracer(trace, ret);
                 return ret;
@@ -570,10 +694,10 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr)
         int ret;
 
         /* start the tracing */
-        ret = trace->init(tr);
+        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 */
@@ -585,6 +709,11 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr)
         trace->reset(tr);
         tracing_start();
 
+        if (!ret && !count) {
+                printk(KERN_CONT ".. no entries found ..");
+                ret = -1;
+        }
+
         return ret;
 }
 #endif /* CONFIG_SYSPROF_TRACER */
@@ -597,7 +726,7 @@ trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
         int ret;
 
         /* start the tracing */
-        ret = trace->init(tr);
+        ret = tracer_init(trace, tr);
         if (ret) {
                 warn_failed_init_tracer(trace, ret);
                 return ret;
@@ -612,6 +741,11 @@ trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
         trace->reset(tr);
         tracing_start();
 
+        if (!ret && !count) {
+                printk(KERN_CONT ".. no entries found ..");
+                ret = -1;
+        }
+
         return ret;
 }
 #endif /* CONFIG_BRANCH_TRACER */