From: Nadia Derbey Date: Wed, 19 Nov 2008 23:36:08 +0000 (-0800) Subject: sysvipc: fix the ipc structures initialization X-Git-Tag: v2.6.28-rc6~47 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=e00b4ff7ebf098b11b11be403921c1cf41d9e321;p=linux-2.6-omap-h63xx.git sysvipc: fix the ipc structures initialization A problem was found while reviewing the code after Bugzilla bug http://bugzilla.kernel.org/show_bug.cgi?id=11796. In ipc_addid(), the newly allocated ipc structure is inserted into the ipcs tree (i.e made visible to readers) without locking it. This is not correct since its initialization continues after it has been inserted in the tree. This patch moves the ipc structure lock initialization + locking before the actual insertion. Signed-off-by: Nadia Derbey Reported-by: Clement Calmels Cc: Manfred Spraul Cc: [2.6.27.x] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/ipc/util.c b/ipc/util.c index 49b3ea615dc..361fd1c96fc 100644 --- a/ipc/util.c +++ b/ipc/util.c @@ -266,9 +266,17 @@ int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) if (ids->in_use >= size) return -ENOSPC; + spin_lock_init(&new->lock); + new->deleted = 0; + rcu_read_lock(); + spin_lock(&new->lock); + err = idr_get_new(&ids->ipcs_idr, new, &id); - if (err) + if (err) { + spin_unlock(&new->lock); + rcu_read_unlock(); return err; + } ids->in_use++; @@ -280,10 +288,6 @@ int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) ids->seq = 0; new->id = ipc_buildid(id, new->seq); - spin_lock_init(&new->lock); - new->deleted = 0; - rcu_read_lock(); - spin_lock(&new->lock); return id; }