[PATCH 11/18] ftrace: Fix locking in register_ftrace_function_probe()

Steven Rostedt
2013-05-11T00:13:48Z

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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

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>
---
kernel/trace/ftrace.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index cacf085..f104c45 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);