diff --git a/ipc/sem.c b/ipc/sem.c
index 0b45a4d..5c882f9 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -1081,6 +1082,7 @@ static struct sem_undo *find_undo(struct ipc_namespace *ns, int semid)
 	new->id_next = sma->undo;
 	sma->undo = new;
 	sem_unlock(sma);
+printk(KERN_ERR "find_undo(%p, %x) new undop %p (for %d sems).\n", ns, semid, new, nsems);
 	un = new;
 	spin_unlock(&ulp->lock);
 out:
@@ -1153,6 +1155,7 @@ retry_undos:
 		error = PTR_ERR(sma);
 		goto out_free;
 	}
+printk(KERN_ERR "find_undo(%p, %x) == %p, using %ld sems.\n", ns, semid, un, sma->sem_nsems);
 
 	/*
 	 * semid identifiers are not unique - find_undo may have