commit 311d16da575f53c3367099579736c1d233efe0dc
author Li Zefan <lizf@cn.fujitsu.com> Tue Dec 08 11:15:11 2009 +0800
committer Frederic Weisbecker <fweisbec@gmail.com> Sun Dec 13 18:37:25 2009 +0100
tree 6fea069fc00f50afac428021989d037f0bb0162f
parent 3b8e4273814a7f9e9a74ece517d9206fea919aaa

ftrace: Return EINVAL when writing invalid val to set_ftrace_filter

Currently it doesn't warn user on invald value:

 # echo nonexist_symbol > set_ftrace_filter
or:
 # echo 'nonexist_symbol:mod:fuse' > set_ftrace_filter

Better make it return failure.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4B1DC4BF.2070003@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

kernel/trace/ftrace.c

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index e51a1bc..08a3fb5 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1724,7 +1724,7 @@
 	return ftrace_match(str, regex, len, type);
 }
 
-static void ftrace_match_records(char *buff, int len, int enable)
+static int ftrace_match_records(char *buff, int len, int enable)
 {
 	unsigned int search_len;
 	struct ftrace_page *pg;
@@ -1733,6 +1733,7 @@
 	char *search;
 	int type;
 	int not;
+	int found = 0;
 
 	flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 	type = filter_parse_regex(buff, len, &search, &not);
@@ -1750,6 +1751,7 @@
 				rec->flags &= ~flag;
 			else
 				rec->flags |= flag;
+			found = 1;
 		}
 		/*
 		 * Only enable filtering if we have a function that
@@ -1759,6 +1761,8 @@
 			ftrace_filtered = 1;
 	} while_for_each_ftrace_rec();
 	mutex_unlock(&ftrace_lock);
+
+	return found;
 }
 
 static int
@@ -1780,7 +1784,7 @@
 		return 1;
 }
 
-static void ftrace_match_module_records(char *buff, char *mod, int enable)
+static int ftrace_match_module_records(char *buff, char *mod, int enable)
 {
 	unsigned search_len = 0;
 	struct ftrace_page *pg;
@@ -1789,6 +1793,7 @@
 	char *search = buff;
 	unsigned long flag;
 	int not = 0;
+	int found = 0;
 
 	flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 
@@ -1819,12 +1824,15 @@
 				rec->flags &= ~flag;
 			else
 				rec->flags |= flag;
+			found = 1;
 		}
 		if (enable && (rec->flags & FTRACE_FL_FILTER))
 			ftrace_filtered = 1;
 
 	} while_for_each_ftrace_rec();
 	mutex_unlock(&ftrace_lock);
+
+	return found;
 }
 
 /*
@@ -1853,8 +1861,9 @@
 	if (!strlen(mod))
 		return -EINVAL;
 
-	ftrace_match_module_records(func, mod, enable);
-	return 0;
+	if (ftrace_match_module_records(func, mod, enable))
+		return 0;
+	return -EINVAL;
 }
 
 static struct ftrace_func_command ftrace_mod_cmd = {
@@ -2151,8 +2160,9 @@
 	func = strsep(&next, ":");
 
 	if (!next) {
-		ftrace_match_records(func, len, enable);
-		return 0;
+		if (ftrace_match_records(func, len, enable))
+			return 0;
+		return ret;
 	}
 
 	/* command found */