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| author | Manfred Spraul <manfred@colorfullife.com> | 2014-12-02 15:59:34 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-03 09:36:03 -0800 |
| commit | e8577d1f0329d4842e8302e289fb2c22156abef4 (patch) | |
| tree | f16f344a3d414db2a0d848b7ca19470b468c902e /ipc/sem.c | |
| parent | 92788ac1eb06e69a822de45e2a8a63fa45eb5be2 (diff) | |
| download | linux-e8577d1f0329d4842e8302e289fb2c22156abef4.tar.gz | |
ipc/sem.c: fully initialize sem_array before making it visible
ipc_addid() makes a new ipc identifier visible to everyone. New objects start as locked, so that the caller can complete the initialization after the call. Within struct sem_array, at least sma->sem_base and sma->sem_nsems are accessed without any locks, therefore this approach doesn't work. Thus: Move the ipc_addid() to the end of the initialization. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Reported-by: Rik van Riel <riel@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Acked-by: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc/sem.c')
| -rw-r--r-- | ipc/sem.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/ipc/sem.c b/ipc/sem.c index 454f6c6020a8..53c3310f41c6 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -507,13 +507,6 @@ 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) { - ipc_rcu_putref(sma, sem_rcu_free); - return id; - } - ns->used_sems += nsems; - sma->sem_base = (struct sem *) &sma[1]; for (i = 0; i < nsems; i++) { @@ -528,6 +521,14 @@ 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) { + ipc_rcu_putref(sma, sem_rcu_free); + return id; + } + ns->used_sems += nsems; + sem_unlock(sma, -1); rcu_read_unlock(); |