Author: Julia Lawall <julia@diku.dk> Add a spin_unlock missing on the error path. The return value of write_reg seems to be completely ignored, so it seems that the lock should be released in every case. The semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // @@ expression E1; @@ * spin_lock(E1,…); * spin_unlock(E1,…); // …