1 files changed, 4 insertions, 2 deletions

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 3641f28c343f..eec648a0d673 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -448,8 +448,10 @@ static char stack_trace_filter_buf[COMMAND_LINE_SIZE+1] __initdata;
 
 static __init int enable_stacktrace(char *str)
 {
-        if (str_has_prefix(str, "_filter="))
-                strncpy(stack_trace_filter_buf, str+8, COMMAND_LINE_SIZE);
+        int len;
+
+        if ((len = str_has_prefix(str, "_filter=")))
+                strncpy(stack_trace_filter_buf, str + len, COMMAND_LINE_SIZE);
 
         stack_tracer_enabled = 1;
         last_stack_tracer_enabled = 1;