If tracer->init() fails, current code will leave current_tracer pointing to an unusable tracer, which at best makes 'current_tracer' report inaccurate value.
Fix the issue by pointing current_tracer to nop tracer, and only update current_tracer with the new one after all the initialization succeeds.
Signed-off-by: Anton Vorontsov anton.vorontsov@linaro.org Acked-by: Steven Rostedt rostedt@goodmis.org --- kernel/trace/trace.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 814ff30..954f7d7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3183,10 +3183,10 @@ static int tracing_set_tracer(const char *buf) } destroy_trace_option_files(topts);
- current_trace = t; + current_trace = &nop_trace;
- topts = create_trace_option_files(current_trace); - if (current_trace->use_max_tr) { + topts = create_trace_option_files(t); + if (t->use_max_tr) { int cpu; /* we need to make per cpu buffer sizes equivalent */ for_each_tracing_cpu(cpu) { @@ -3206,6 +3206,7 @@ static int tracing_set_tracer(const char *buf) goto out; }
+ current_trace = t; trace_branch_enable(tr); out: mutex_unlock(&trace_types_lock);