[PATCH] tracing: Reset the function filter after completing trampoline/graph selftest

From: Li Huafei
Date: Mon Apr 18 2022 - 03:41:11 EST


The direct trampoline and graph coexistence test sets global_ops to
trace only 'trace_selftest_dynamic_test_func', but does not reset it
after the test is completed, resulting in the function filter being set
already after the system starts. Although it can be reset through the
tracefs interface, it is more or less confusing to the user, and we
should reset it to trace all functions after the trampoline/graph test
completes.

Fixes: 130c08065848 ("tracing: Add trampoline/graph selftest")
Signed-off-by: Li Huafei <lihuafei1@xxxxxxxxxx>
---
kernel/trace/trace_selftest.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index abcadbe933bb..e89f72571f8e 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -866,12 +866,12 @@ trace_selftest_startup_function_graph(struct tracer *trace,
ret = register_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME,
(unsigned long) trace_direct_tramp);
if (ret)
- goto out;
+ goto reset_filter;

ret = register_ftrace_graph(&fgraph_ops);
if (ret) {
warn_failed_init_tracer(trace, ret);
- goto out;
+ goto reset_filter;
}

DYN_FTRACE_TEST_NAME();
@@ -887,14 +887,18 @@ trace_selftest_startup_function_graph(struct tracer *trace,
ret = unregister_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME,
(unsigned long) trace_direct_tramp);
if (ret)
- goto out;
+ goto reset_filter;

tracing_start();

if (!ret && !count) {
ret = -1;
- goto out;
+ goto reset_filter;
}
+
+reset_filter:
+ /* Enable tracing on all functions again */
+ ftrace_set_global_filter(NULL, 0, 1);
#endif

/* Don't test dynamic tracing, the function tracer already did */
--
2.17.1