drivers/char/random.c: fix boot id uniqueness race
[~shefty/rdma-dev.git] / drivers / char / random.c
index 54ca8b2..4ec04a7 100644 (file)
@@ -1260,10 +1260,15 @@ static int proc_do_uuid(ctl_table *table, int write,
        uuid = table->data;
        if (!uuid) {
                uuid = tmp_uuid;
-               uuid[8] = 0;
-       }
-       if (uuid[8] == 0)
                generate_random_uuid(uuid);
+       } else {
+               static DEFINE_SPINLOCK(bootid_spinlock);
+
+               spin_lock(&bootid_spinlock);
+               if (!uuid[8])
+                       generate_random_uuid(uuid);
+               spin_unlock(&bootid_spinlock);
+       }
 
        sprintf(buf, "%pU", uuid);