1 files changed, 283 insertions, 21 deletions

diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 288541f977fb..2c00a691a540 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -103,54 +103,67 @@ static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret)
 
 static int trace_selftest_test_probe1_cnt;
 static void trace_selftest_test_probe1_func(unsigned long ip,
-                                            unsigned long pip)
+                                            unsigned long pip,
+                                            struct ftrace_ops *op,
+                                            struct pt_regs *pt_regs)
 {
         trace_selftest_test_probe1_cnt++;
 }
 
 static int trace_selftest_test_probe2_cnt;
 static void trace_selftest_test_probe2_func(unsigned long ip,
-                                            unsigned long pip)
+                                            unsigned long pip,
+                                            struct ftrace_ops *op,
+                                            struct pt_regs *pt_regs)
 {
         trace_selftest_test_probe2_cnt++;
 }
 
 static int trace_selftest_test_probe3_cnt;
 static void trace_selftest_test_probe3_func(unsigned long ip,
-                                            unsigned long pip)
+                                            unsigned long pip,
+                                            struct ftrace_ops *op,
+                                            struct pt_regs *pt_regs)
 {
         trace_selftest_test_probe3_cnt++;
 }
 
 static int trace_selftest_test_global_cnt;
 static void trace_selftest_test_global_func(unsigned long ip,
-                                            unsigned long pip)
+                                            unsigned long pip,
+                                            struct ftrace_ops *op,
+                                            struct pt_regs *pt_regs)
 {
         trace_selftest_test_global_cnt++;
 }
 
 static int trace_selftest_test_dyn_cnt;
 static void trace_selftest_test_dyn_func(unsigned long ip,
-                                         unsigned long pip)
+                                         unsigned long pip,
+                                         struct ftrace_ops *op,
+                                         struct pt_regs *pt_regs)
 {
         trace_selftest_test_dyn_cnt++;
 }
 
 static struct ftrace_ops test_probe1 = {
         .func                   = trace_selftest_test_probe1_func,
+        .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 };
 
 static struct ftrace_ops test_probe2 = {
         .func                   = trace_selftest_test_probe2_func,
+        .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 };
 
 static struct ftrace_ops test_probe3 = {
         .func                   = trace_selftest_test_probe3_func,
+        .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 };
 
 static struct ftrace_ops test_global = {
-        .func                   = trace_selftest_test_global_func,
-        .flags                  = FTRACE_OPS_FL_GLOBAL,
+        .func           = trace_selftest_test_global_func,
+        .flags          = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE,
 };
 
 static void print_counts(void)
@@ -393,10 +406,253 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
 
         return ret;
 }
+
+static int trace_selftest_recursion_cnt;
+static void trace_selftest_test_recursion_func(unsigned long ip,
+                                               unsigned long pip,
+                                               struct ftrace_ops *op,
+                                               struct pt_regs *pt_regs)
+{
+        /*
+         * This function is registered without the recursion safe flag.
+         * The ftrace infrastructure should provide the recursion
+         * protection. If not, this will crash the kernel!
+         */
+        trace_selftest_recursion_cnt++;
+        DYN_FTRACE_TEST_NAME();
+}
+
+static void trace_selftest_test_recursion_safe_func(unsigned long ip,
+                                                    unsigned long pip,
+                                                    struct ftrace_ops *op,
+                                                    struct pt_regs *pt_regs)
+{
+        /*
+         * We said we would provide our own recursion. By calling
+         * this function again, we should recurse back into this function
+         * and count again. But this only happens if the arch supports
+         * all of ftrace features and nothing else is using the function
+         * tracing utility.
+         */
+        if (trace_selftest_recursion_cnt++)
+                return;
+        DYN_FTRACE_TEST_NAME();
+}
+
+static struct ftrace_ops test_rec_probe = {
+        .func                   = trace_selftest_test_recursion_func,
+};
+
+static struct ftrace_ops test_recsafe_probe = {
+        .func                   = trace_selftest_test_recursion_safe_func,
+        .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
+};
+
+static int
+trace_selftest_function_recursion(void)
+{
+        int save_ftrace_enabled = ftrace_enabled;
+        int save_tracer_enabled = tracer_enabled;
+        char *func_name;
+        int len;
+        int ret;
+        int cnt;
+
+        /* The previous test PASSED */
+        pr_cont("PASSED\n");
+        pr_info("Testing ftrace recursion: ");
+
+
+        /* enable tracing, and record the filter function */
+        ftrace_enabled = 1;
+        tracer_enabled = 1;
+
+        /* Handle PPC64 '.' name */
+        func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
+        len = strlen(func_name);
+
+        ret = ftrace_set_filter(&test_rec_probe, func_name, len, 1);
+        if (ret) {
+                pr_cont("*Could not set filter* ");
+                goto out;
+        }
+
+        ret = register_ftrace_function(&test_rec_probe);
+        if (ret) {
+                pr_cont("*could not register callback* ");
+                goto out;
+        }
+
+        DYN_FTRACE_TEST_NAME();
+
+        unregister_ftrace_function(&test_rec_probe);
+
+        ret = -1;
+        if (trace_selftest_recursion_cnt != 1) {
+                pr_cont("*callback not called once (%d)* ",
+                        trace_selftest_recursion_cnt);
+                goto out;
+        }
+
+        trace_selftest_recursion_cnt = 1;
+
+        pr_cont("PASSED\n");
+        pr_info("Testing ftrace recursion safe: ");
+
+        ret = ftrace_set_filter(&test_recsafe_probe, func_name, len, 1);
+        if (ret) {
+                pr_cont("*Could not set filter* ");
+                goto out;
+        }
+
+        ret = register_ftrace_function(&test_recsafe_probe);
+        if (ret) {
+                pr_cont("*could not register callback* ");
+                goto out;
+        }
+
+        DYN_FTRACE_TEST_NAME();
+
+        unregister_ftrace_function(&test_recsafe_probe);
+
+        /*
+         * If arch supports all ftrace features, and no other task
+         * was on the list, we should be fine.
+         */
+        if (!ftrace_nr_registered_ops() && !FTRACE_FORCE_LIST_FUNC)
+                cnt = 2; /* Should have recursed */
+        else
+                cnt = 1;
+
+        ret = -1;
+        if (trace_selftest_recursion_cnt != cnt) {
+                pr_cont("*callback not called expected %d times (%d)* ",
+                        cnt, trace_selftest_recursion_cnt);
+                goto out;
+        }
+
+        ret = 0;
+out:
+        ftrace_enabled = save_ftrace_enabled;
+        tracer_enabled = save_tracer_enabled;
+
+        return ret;
+}
 #else
 # define trace_selftest_startup_dynamic_tracing(trace, tr, func) ({ 0; })
+# define trace_selftest_function_recursion() ({ 0; })
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
+static enum {
+        TRACE_SELFTEST_REGS_START,
+        TRACE_SELFTEST_REGS_FOUND,
+        TRACE_SELFTEST_REGS_NOT_FOUND,
+} trace_selftest_regs_stat;
+
+static void trace_selftest_test_regs_func(unsigned long ip,
+                                          unsigned long pip,
+                                          struct ftrace_ops *op,
+                                          struct pt_regs *pt_regs)
+{
+        if (pt_regs)
+                trace_selftest_regs_stat = TRACE_SELFTEST_REGS_FOUND;
+        else
+                trace_selftest_regs_stat = TRACE_SELFTEST_REGS_NOT_FOUND;
+}
+
+static struct ftrace_ops test_regs_probe = {
+        .func           = trace_selftest_test_regs_func,
+        .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_SAVE_REGS,
+};
+
+static int
+trace_selftest_function_regs(void)
+{
+        int save_ftrace_enabled = ftrace_enabled;
+        int save_tracer_enabled = tracer_enabled;
+        char *func_name;
+        int len;
+        int ret;
+        int supported = 0;
+
+#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS
+        supported = 1;
+#endif
+
+        /* The previous test PASSED */
+        pr_cont("PASSED\n");
+        pr_info("Testing ftrace regs%s: ",
+                !supported ? "(no arch support)" : "");
+
+        /* enable tracing, and record the filter function */
+        ftrace_enabled = 1;
+        tracer_enabled = 1;
+
+        /* Handle PPC64 '.' name */
+        func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
+        len = strlen(func_name);
+
+        ret = ftrace_set_filter(&test_regs_probe, func_name, len, 1);
+        /*
+         * If DYNAMIC_FTRACE is not set, then we just trace all functions.
+         * This test really doesn't care.
+         */
+        if (ret && ret != -ENODEV) {
+                pr_cont("*Could not set filter* ");
+                goto out;
+        }
+
+        ret = register_ftrace_function(&test_regs_probe);
+        /*
+         * Now if the arch does not support passing regs, then this should
+         * have failed.
+         */
+        if (!supported) {
+                if (!ret) {
+                        pr_cont("*registered save-regs without arch support* ");
+                        goto out;
+                }
+                test_regs_probe.flags |= FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED;
+                ret = register_ftrace_function(&test_regs_probe);
+        }
+        if (ret) {
+                pr_cont("*could not register callback* ");
+                goto out;
+        }
+
+
+        DYN_FTRACE_TEST_NAME();
+
+        unregister_ftrace_function(&test_regs_probe);
+
+        ret = -1;
+
+        switch (trace_selftest_regs_stat) {
+        case TRACE_SELFTEST_REGS_START:
+                pr_cont("*callback never called* ");
+                goto out;
+
+        case TRACE_SELFTEST_REGS_FOUND:
+                if (supported)
+                        break;
+                pr_cont("*callback received regs without arch support* ");
+                goto out;
+
+        case TRACE_SELFTEST_REGS_NOT_FOUND:
+                if (!supported)
+                        break;
+                pr_cont("*callback received NULL regs* ");
+                goto out;
+        }
+
+        ret = 0;
+out:
+        ftrace_enabled = save_ftrace_enabled;
+        tracer_enabled = save_tracer_enabled;
+
+        return ret;
+}
+
 /*
  * Simple verification test of ftrace function tracer.
  * Enable ftrace, sleep 1/10 second, and then read the trace
@@ -442,7 +698,14 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
 
         ret = trace_selftest_startup_dynamic_tracing(trace, tr,
                                                      DYN_FTRACE_TEST_NAME);
+        if (ret)
+                goto out;
 
+        ret = trace_selftest_function_recursion();
+        if (ret)
+                goto out;
+
+        ret = trace_selftest_function_regs();
  out:
         ftrace_enabled = save_ftrace_enabled;
         tracer_enabled = save_tracer_enabled;
@@ -778,6 +1041,8 @@ static int trace_wakeup_test_thread(void *data)
         set_current_state(TASK_INTERRUPTIBLE);
         schedule();
 
+        complete(x);
+
         /* we are awake, now wait to disappear */
         while (!kthread_should_stop()) {
                 /*
@@ -821,24 +1086,21 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
         /* reset the max latency */
         tracing_max_latency = 0;
 
-        /* sleep to let the RT thread sleep too */
-        msleep(100);
+        while (p->on_rq) {
+                /*
+                 * Sleep to make sure the RT thread is asleep too.
+                 * On virtual machines we can't rely on timings,
+                 * but we want to make sure this test still works.
+                 */
+                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.
-         */
+        init_completion(&isrt);
 
         wake_up_process(p);
 
-        /* give a little time to let the thread wake up */
-        msleep(100);
+        /* Wait for the task to wake up */
+        wait_for_completion(&isrt);
 
         /* stop the tracing. */
         tracing_stop();