[for-next][PATCH 3/4] tracing: Do note expose stack_trace_filter without DYNAMIC_FTRACE

Steven Rostedt
2017-07-12T12:57:32Z

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From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The "stack_trace_filter" file only makes sense if DYNAMIC_FTRACE is
configured in. If it is not, then the user can not filter any functions.

Not only that, the open function causes warnings when DYNAMIC_FTRACE is not
set.

Link: http://lkml.kernel.org/r/20170710110521.600806-1-arnd@arndb.de

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace_stack.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index b4a751e8f9d6..a4df67cbc711 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -406,6 +406,8 @@ static const struct file_operations stack_trace_fops = {
.release = seq_release,
};

+#ifdef CONFIG_DYNAMIC_FTRACE
+
static int
stack_trace_filter_open(struct inode *inode, struct file *file)
{
@@ -423,6 +425,8 @@ static const struct file_operations stack_trace_filter_fops = {
.release = ftrace_regex_release,
};

+#endif /* CONFIG_DYNAMIC_FTRACE */
+
int
stack_trace_sysctl(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
@@ -477,8 +481,10 @@ static __init int stack_trace_init(void)
trace_create_file("stack_trace", 0444, d_tracer,
NULL, &stack_trace_fops);

+#ifdef CONFIG_DYNAMIC_FTRACE
trace_create_file("stack_trace_filter", 0444, d_tracer,
&trace_ops, &stack_trace_filter_fops);
+#endif

if (stack_trace_filter_buf[0])
ftrace_set_early_filter(&trace_ops, stack_trace_filter_buf, 1);
--
2.10.2