[PATCH] Fix ipc entries removal

Pavel Emelianov
2006-10-30T12:11:50Z

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This patch fixes two issuses related to ipc_ids->entries freeing.

1. When freeing ipc namespace we need to free entries allocated
with ipc_init_ids().

2. When removing old entries in grow_ary() ipc_rcu_putref()
may be called on entries set to &ids->nullentry earlier in
ipc_init_ids().
This is almost impossible without namespaces, but with
them this situation becomes possible.

Found during OpenVZ testing after obvious leaks in beancounters.

Signed-off-by: Pavel Emelianov <xemul@openvz.org>

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--- ./ipc/msg.c.ipcfx 2006-10-30 14:53:07.000000000 +0300
+++ ./ipc/msg.c 2006-10-30 15:00:08.000000000 +0300
@@ -124,6 +124,7 @@ void msg_exit_ns(struct ipc_namespace *n
}
mutex_unlock(&msg_ids(ns).mutex);

+ ipc_fini_ids(ns->ids[IPC_MSG_IDS]);
kfree(ns->ids[IPC_MSG_IDS]);
ns->ids[IPC_MSG_IDS] = NULL;
}
--- ./ipc/sem.c.ipcfx 2006-10-30 14:53:07.000000000 +0300
+++ ./ipc/sem.c 2006-10-30 14:59:44.000000000 +0300
@@ -161,6 +161,7 @@ void sem_exit_ns(struct ipc_namespace *n
}
mutex_unlock(&sem_ids(ns).mutex);

+ ipc_fini_ids(ns->ids[IPC_SEM_IDS]);
kfree(ns->ids[IPC_SEM_IDS]);
ns->ids[IPC_SEM_IDS] = NULL;
}
--- ./ipc/shm.c.ipcfx 2006-10-30 14:53:07.000000000 +0300
+++ ./ipc/shm.c 2006-10-30 14:59:57.000000000 +0300
@@ -116,6 +116,7 @@ void shm_exit_ns(struct ipc_namespace *n
}
mutex_unlock(&shm_ids(ns).mutex);

+ ipc_fini_ids(ns->ids[IPC_SHM_IDS]);
kfree(ns->ids[IPC_SHM_IDS]);
ns->ids[IPC_SHM_IDS] = NULL;
}
--- ./ipc/util.c.ipcfx 2006-10-26 17:51:58.000000000 +0400
+++ ./ipc/util.c 2006-10-30 14:59:23.000000000 +0300
@@ -301,7 +301,7 @@ static int grow_ary(struct ipc_ids* ids,
*/
rcu_assign_pointer(ids->entries, new);

- ipc_rcu_putref(old);
+ __ipc_fini_ids(ids, old);
return newsize;
}

--- ./ipc/util.h.ipcfx 2006-10-26 17:51:58.000000000 +0400
+++ ./ipc/util.h 2006-10-30 14:59:09.000000000 +0300
@@ -83,6 +83,18 @@ void* ipc_rcu_alloc(int size);
void ipc_rcu_getref(void *ptr);
void ipc_rcu_putref(void *ptr);

+static inline void __ipc_fini_ids(struct ipc_ids *ids,
+ struct ipc_id_ary *entries)
+{
+ if (entries != &ids->nullentry)
+ ipc_rcu_putref(entries);
+}
+
+static inline void ipc_fini_ids(struct ipc_ids *ids)
+{
+ __ipc_fini_ids(ids, ids->entries);
+}
+
struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id);
struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id);
void ipc_lock_by_ptr(struct kern_ipc_perm *ipcp);