X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=ipc%2Fsem.c;h=b31c3ef43c913f4cea4d583703ea015c9c777a2f;hp=5215a81420df9b1802dd9f6c40c465f1b63a2bbd;hb=f63b2b3204ea962e9cc34a223771ec973694f8bf;hpb=b4949b84567f3ae1227d076fc95bbd8efea06506

diff --git a/ipc/sem.c b/ipc/sem.c
index 5215a81420df..b31c3ef43c91 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -314,14 +314,6 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
 		return retval;
 	}
 
-	id = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni);
-	if (id < 0) {
-		security_sem_free(sma);
-		ipc_rcu_putref(sma);
-		return id;
-	}
-	ns->used_sems += nsems;
-
 	sma->sem_base = (struct sem *) &sma[1];
 
 	for (i = 0; i < nsems; i++)
@@ -332,6 +324,15 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
 	INIT_LIST_HEAD(&sma->list_id);
 	sma->sem_nsems = nsems;
 	sma->sem_ctime = get_seconds();
+
+	id = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni);
+	if (id < 0) {
+		security_sem_free(sma);
+		ipc_rcu_putref(sma);
+		return id;
+	}
+	ns->used_sems += nsems;
+
 	sem_unlock(sma);
 
 	return sma->sem_perm.id;
@@ -1606,16 +1607,27 @@ void exit_sem(struct task_struct *tsk)
 		rcu_read_lock();
 		un = list_entry_rcu(ulp->list_proc.next,
 				    struct sem_undo, list_proc);
-		if (&un->list_proc == &ulp->list_proc)
-			semid = -1;
-		 else
-			semid = un->semid;
+		if (&un->list_proc == &ulp->list_proc) {
+			/*
+			 * We must wait for freeary() before freeing this ulp,
+			 * in case we raced with last sem_undo. There is a small
+			 * possibility where we exit while freeary() didn't
+			 * finish unlocking sem_undo_list.
+			 */
+			spin_unlock_wait(&ulp->lock);
+			rcu_read_unlock();
+			break;
+		}
+		spin_lock(&ulp->lock);
+		semid = un->semid;
+		spin_unlock(&ulp->lock);
 		rcu_read_unlock();
 
+		/* exit_sem raced with IPC_RMID, nothing to do */
 		if (semid == -1)
-			break;
+			continue;
 
-		sma = sem_lock_check(tsk->nsproxy->ipc_ns, un->semid);
+		sma = sem_lock_check(tsk->nsproxy->ipc_ns, semid);
 
 		/* exit_sem raced with IPC_RMID, nothing to do */
 		if (IS_ERR(sma))