[PATCH 2/4] ksym_tracer: Fix to allow writing newline to ksym_trace_filter

[Li Zefan <lizf@cn.fujitsu.com>]

It used to work, but now doesn't:

 # echo > ksym_filter
 bash: echo: write error: Invalid argument

It's caused by d954fbf0ff6b5fdfb32350e85a2f15d3db976506
("tracing: Fix wrong usage of strstrip in trace_ksyms").

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 kernel/trace/trace_ksym.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index 340b6ff..160a8d8 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -299,8 +299,8 @@ static ssize_t ksym_trace_filter_write(struct file *file,
 	 * 2: echo 0 > ksym_trace_filter
 	 * 3: echo "*:---" > ksym_trace_filter
 	 */
-	if (!buf[0] || !strcmp(buf, "0") ||
-	    !strcmp(buf, "*:---")) {
+	if (!input_string[0] || !strcmp(input_string, "0") ||
+	    !strcmp(input_string, "*:---")) {
 		__ksym_trace_reset();
 		ret = 0;
 		goto out;
-- 
1.6.3