ftrace: return an error when setting a nonexistent tracer
When one try to set a nonexistent tracer, no error is returned
as if the name of the tracer was correct.
We should return -EINVAL.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index caa4051..78d5661 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2381,9 +2381,11 @@
struct tracer *t;
char buf[max_tracer_type_len+1];
int i;
+ size_t ret;
if (cnt > max_tracer_type_len)
cnt = max_tracer_type_len;
+ ret = cnt;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
@@ -2399,7 +2401,11 @@
if (strcmp(t->name, buf) == 0)
break;
}
- if (!t || t == current_trace)
+ if (!t) {
+ ret = -EINVAL;
+ goto out;
+ }
+ if (t == current_trace)
goto out;
if (current_trace && current_trace->reset)
@@ -2412,9 +2418,10 @@
out:
mutex_unlock(&trace_types_lock);
- filp->f_pos += cnt;
+ if (ret == cnt)
+ filp->f_pos += cnt;
- return cnt;
+ return ret;
}
static ssize_t