ftrace: Have ftrace_regex_write() return either read or error
As ftrace_regex_write() reads the result of ftrace_process_regex()
which can sometimes return a positive number, only consider a
failure if the return is negative. Otherwise, it will skip possible
other registered probes and by returning a positive number that
wasn't read, it will confuse the user processes doing the writing.
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 8a5c017..d85a0ad 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3276,7 +3276,7 @@
ret = ftrace_process_regex(iter->hash, parser->buffer,
parser->idx, enable);
trace_parser_clear(parser);
- if (ret)
+ if (ret < 0)
goto out_unlock;
}