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-rw-r--r--ipc/sem.c16
1 files changed, 7 insertions, 9 deletions
diff --git a/ipc/sem.c b/ipc/sem.c
index 1f8f01a542de..8486a5bb6d29 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -269,6 +269,8 @@ static inline void sem_unlock(struct sem_array *sma, int locknum)
/*
* sem_lock_(check_) routines are called in the paths where the rw_mutex
* is not held.
+ *
+ * The caller holds the RCU read lock.
*/
static inline struct sem_array *sem_obtain_lock(struct ipc_namespace *ns,
int id, struct sembuf *sops, int nsops, int *locknum)
@@ -276,12 +278,9 @@ static inline struct sem_array *sem_obtain_lock(struct ipc_namespace *ns,
struct kern_ipc_perm *ipcp;
struct sem_array *sma;
- rcu_read_lock();
ipcp = ipc_obtain_object(&sem_ids(ns), id);
- if (IS_ERR(ipcp)) {
- sma = ERR_CAST(ipcp);
- goto err;
- }
+ if (IS_ERR(ipcp))
+ return ERR_CAST(ipcp);
sma = container_of(ipcp, struct sem_array, sem_perm);
*locknum = sem_lock(sma, sops, nsops);
@@ -293,10 +292,7 @@ static inline struct sem_array *sem_obtain_lock(struct ipc_namespace *ns,
return container_of(ipcp, struct sem_array, sem_perm);
sem_unlock(sma, *locknum);
- sma = ERR_PTR(-EINVAL);
-err:
- rcu_read_unlock();
- return sma;
+ return ERR_PTR(-EINVAL);
}
static inline struct sem_array *sem_obtain_object(struct ipc_namespace *ns, int id)
@@ -1680,6 +1676,7 @@ sleep_again:
goto out_free;
}
+ rcu_read_lock();
sma = sem_obtain_lock(ns, semid, sops, nsops, &locknum);
/*
@@ -1691,6 +1688,7 @@ sleep_again:
* Array removed? If yes, leave without sem_unlock().
*/
if (IS_ERR(sma)) {
+ rcu_read_unlock();
goto out_free;
}