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authorJiri Olsa <jolsa@redhat.com>2021-10-08 12:13:32 +0300
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-10-21 06:44:44 +0300
commit130c08065848a98163b243b55e99f66c24609efb (patch)
treeb38fd7cd10f7c48d3125507b582fea448669f1b0
parent0c0593b45c9b4e5b212ffb3fb28bb8d3c0ec0dc8 (diff)
downloadlinux-130c08065848a98163b243b55e99f66c24609efb.tar.xz
tracing: Add trampoline/graph selftest
Adding selftest for checking that direct trampoline can co-exist together with graph tracer on same function. This is supported for CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS config option, which is defined only for x86_64 for now. Link: https://lkml.kernel.org/r/20211008091336.33616-5-jolsa@kernel.org Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
-rw-r--r--kernel/trace/trace_selftest.c54
1 files changed, 53 insertions, 1 deletions
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 875b4f1a0476..3404a245417e 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -784,6 +784,8 @@ static struct fgraph_ops fgraph_ops __initdata = {
.retfunc = &trace_graph_return,
};
+noinline __noclone static void trace_direct_tramp(void) { }
+
/*
* Pretty much the same than for the function tracer from which the selftest
* has been borrowed.
@@ -794,6 +796,7 @@ trace_selftest_startup_function_graph(struct tracer *trace,
{
int ret;
unsigned long count;
+ char *func_name __maybe_unused;
#ifdef CONFIG_DYNAMIC_FTRACE
if (ftrace_filter_param) {
@@ -842,8 +845,57 @@ trace_selftest_startup_function_graph(struct tracer *trace,
goto out;
}
- /* Don't test dynamic tracing, the function tracer already did */
+#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
+ tracing_reset_online_cpus(&tr->array_buffer);
+ set_graph_array(tr);
+
+ /*
+ * Some archs *cough*PowerPC*cough* add characters to the
+ * start of the function names. We simply put a '*' to
+ * accommodate them.
+ */
+ func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
+ ftrace_set_global_filter(func_name, strlen(func_name), 1);
+
+ /*
+ * Register direct function together with graph tracer
+ * and make sure we get graph trace.
+ */
+ ret = register_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME,
+ (unsigned long) trace_direct_tramp);
+ if (ret)
+ goto out;
+
+ ret = register_ftrace_graph(&fgraph_ops);
+ if (ret) {
+ warn_failed_init_tracer(trace, ret);
+ goto out;
+ }
+
+ DYN_FTRACE_TEST_NAME();
+
+ count = 0;
+
+ tracing_stop();
+ /* check the trace buffer */
+ ret = trace_test_buffer(&tr->array_buffer, &count);
+
+ unregister_ftrace_graph(&fgraph_ops);
+
+ ret = unregister_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME,
+ (unsigned long) trace_direct_tramp);
+ if (ret)
+ goto out;
+
+ tracing_start();
+ if (!ret && !count) {
+ ret = -1;
+ goto out;
+ }
+#endif
+
+ /* Don't test dynamic tracing, the function tracer already did */
out:
/* Stop it if we failed */
if (ret)