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>

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index e51a1bcb7bed3e8dc93430d37d89d2179e7e5d2a..08a3fb5b3187b294bfb96068285f89b36458e230 100644 (file)
--- 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 */