The comment that explains ipc_obtain_object_check is wrong: The function checks the sequence number, not the reference counter. Note that checking the reference counter would be meaningless: The reference counter is decreased without holding any locks, thus an object with kern_ipc_perm.deleted=true may disappear at the end of the next rcu grace period.
Signed-off-by: Manfred Spraul <manf...@colorfullife.com> Reviewed-by: Davidlohr Bueso <dbu...@suse.de> --- ipc/util.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/ipc/util.c b/ipc/util.c index cffd12240f67..5cc37066e659 100644 --- a/ipc/util.c +++ b/ipc/util.c @@ -628,8 +628,8 @@ struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) * @ids: ipc identifier set * @id: ipc id to look for * - * Similar to ipc_obtain_object_idr() but also checks - * the ipc object reference counter. + * Similar to ipc_obtain_object_idr() but also checks the ipc object + * sequence number. * * Call inside the RCU critical section. * The ipc object is *not* locked on exit. -- 2.17.1
