fail_function: Remove a redundant mutex unlock

Fix a mutex_unlock() issue where before copy_from_user() is
not called mutex_locked.

Fixes: 4b1a29a7f542 ("error-injection: Support fault injection framework")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Luo Meng <luomeng12@huawei.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/bpf/160570737118.263807.8358435412898356284.stgit@devnote2

diff --git a/kernel/fail_function.c b/kernel/fail_function.c
index 63b3491..b0b1ad9 100644 (file)
--- a/kernel/fail_function.c
+++ b/kernel/fail_function.c
@@ -253,7 +253,7 @@ static ssize_t fei_write(struct file *file, const char __user *buffer,
 
        if (copy_from_user(buf, buffer, count)) {
                ret = -EFAULT;
-               goto out;
+               goto out_free;
        }
        buf[count] = '\0';
        sym = strstrip(buf);
@@ -307,8 +307,9 @@ static ssize_t fei_write(struct file *file, const char __user *buffer,
                ret = count;
        }
 out:
-       kfree(buf);
        mutex_unlock(&fei_lock);
+out_free:
+       kfree(buf);
        return ret;
 }