kernel: fix save allowlist

kernel/allowlist.c

@@ -1,3 +1,5 @@
+#include <linux/mutex.h>
+#include <linux/task_work.h>
 #include <linux/capability.h>
 #include <linux/compiler.h>
 #include <linux/fs.h>
@@ -357,7 +359,7 @@ bool ksu_get_allow_list(int *array, int *length, bool allow)
     return true;
 }
 
-void persistent_allow_list()
+static void do_persistent_allow_list(struct callback_head *_cb)
 {
     u32 magic = FILE_MAGIC;
     u32 version = FILE_FORMAT_VERSION;
@@ -365,6 +367,7 @@ void persistent_allow_list()
     struct list_head *pos = NULL;
     loff_t off = 0;
 
+    mutex_lock(&allowlist_mutex);
     struct file *fp =
         filp_open(KERNEL_SU_ALLOWLIST, O_WRONLY | O_CREAT | O_TRUNC, 0644);
     if (IS_ERR(fp)) {
@@ -393,6 +396,29 @@ void persistent_allow_list()
 
 exit:
     filp_close(fp, 0);
+    mutex_unlock(&allowlist_mutex);
+}
+
+void persistent_allow_list()
+{
+    struct task_struct *tsk;
+
+    tsk = get_pid_task(find_vpid(1), PIDTYPE_PID);
+    if (!tsk) {
+        pr_err("save_allow_list find init task err\n");
+        return;
+    }
+
+    struct callback_head *cb =
+        kzalloc(sizeof(struct callback_head), GFP_KERNEL);
+    if (!cb) {
+        pr_err("save_allow_list alloc cb err\b");
+        return;
+    }
+    cb->func = do_persistent_allow_list;
+    task_work_add(tsk, cb, TWA_RESUME);
+
+    put_task_struct(tsk);
 }
 
 void ksu_load_allow_list()