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>

1 files changed, 16 insertions, 6 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index e51a1bcb7bed..08a3fb5b3187 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1724,7 +1724,7 @@ ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
         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 @@ static void ftrace_match_records(char *buff, int len, int enable)
         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 @@ static void ftrace_match_records(char *buff, int len, int enable)
                                 rec->flags &= ~flag;
                         else
                                 rec->flags |= flag;
+                        found = 1;
                 }
                 /*
                  * Only enable filtering if we have a function that
@@ -1759,6 +1761,8 @@ static void ftrace_match_records(char *buff, int len, int enable)
                         ftrace_filtered = 1;
         } while_for_each_ftrace_rec();
         mutex_unlock(&ftrace_lock);
+
+        return found;
 }
 
 static int
@@ -1780,7 +1784,7 @@ ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
                 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 @@ static void ftrace_match_module_records(char *buff, char *mod, int enable)
         char *search = buff;
         unsigned long flag;
         int not = 0;
+        int found = 0;
 
         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 
@@ -1819,12 +1824,15 @@ static void ftrace_match_module_records(char *buff, char *mod, int enable)
                                 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 @@ ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
         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 @@ static int ftrace_process_regex(char *buff, int len, int enable)
         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 */