ftrace: Fix locking in register_ftrace_function_probe()

The iteration of the ftrace function list and the call to
ftrace_match_record() need to be protected by the ftrace_lock.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index cacf0856191e..f104c45cbcc1 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3017,14 +3017,16 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
         if (!hash) {
                 count = -ENOMEM;
-                goto out_unlock;
+                goto out;
         }
 
         if (unlikely(ftrace_disabled)) {
                 count = -ENODEV;
-                goto out_unlock;
+                goto out;
         }
 
+        mutex_lock(&ftrace_lock);
+
         do_for_each_ftrace_rec(pg, rec) {
 
                 if (!ftrace_match_record(rec, NULL, search, len, type))
@@ -3070,15 +3072,15 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 
         } while_for_each_ftrace_rec();
 
-        mutex_lock(&ftrace_lock);
         ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
         if (ret < 0)
                 count = ret;
 
         __enable_ftrace_function_probe();
-        mutex_unlock(&ftrace_lock);
 
  out_unlock:
+        mutex_unlock(&ftrace_lock);
+ out:
         mutex_unlock(&trace_probe_ops.regex_lock);
         free_ftrace_hash(hash);