Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752656AbZCQX1W (ORCPT ); Tue, 17 Mar 2009 19:27:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751872AbZCQX1L (ORCPT ); Tue, 17 Mar 2009 19:27:11 -0400 Received: from fg-out-1718.google.com ([72.14.220.159]:32555 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751456AbZCQX1J (ORCPT ); Tue, 17 Mar 2009 19:27:09 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:mime-version:content-type :content-disposition:user-agent; b=AeGozNduwdronGo2JRolNQklPTv3LPqrUi5ieKaD2DGEd3gsUHb8clYh+b44o2MxRH pVmeWJlhwawTNVDqQjSUV3YccaBo3lDl4NWQCa3b/3CNxWLLzosyFQDSbhdZMsfx8xYp +8euKxwfeamymLB2cpV2+YzjIuQUqchU+YLIw= Date: Wed, 18 Mar 2009 02:34:18 +0300 From: Alexey Dobriyan To: dhowells@redhat.com, serue@us.ibm.com Cc: linux-kernel@vger.kernel.org Subject: struct user_namespace::creator Message-ID: <20090317233417.GA6195@x200.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2312 Lines: 75 What is struct user_namespace::creator needed for? The scheme when struct user pins struct user_namespace which frees ->creator which is supposed to pind user_ns is really icky. I tried this (inclomplete) patch and nothing bad happened so far with CLONE_NEWUSER: --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -12,7 +12,6 @@ struct user_namespace { struct kref kref; struct hlist_head uidhash_table[UIDHASH_SZ]; - struct user_struct *creator; struct work_struct destroyer; }; diff --git a/kernel/user.c b/kernel/user.c index fbb300e..1cecb8c 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -22,7 +22,6 @@ struct user_namespace init_user_ns = { .kref = { .refcount = ATOMIC_INIT(1), }, - .creator = &root_user, }; EXPORT_SYMBOL_GPL(init_user_ns); @@ -48,9 +47,8 @@ static struct kmem_cache *uid_cachep; */ static DEFINE_SPINLOCK(uidhash_lock); -/* root_user.__count is 2, 1 for init task cred, 1 for init_user_ns->creator */ struct user_struct root_user = { - .__count = ATOMIC_INIT(2), + .__count = ATOMIC_INIT(1), /* init_cred */ .processes = ATOMIC_INIT(1), .files = ATOMIC_INIT(0), .sigpending = ATOMIC_INIT(0), --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -12,10 +12,6 @@ #include /* - * Create a new user namespace, deriving the creator from the user in the - * passed credentials, and replacing that user with the new root user for the - * new namespace. - * * This is called by copy_creds(), which will finish setting the target task's * credentials. */ @@ -42,7 +38,6 @@ int create_user_ns(struct cred *new) } /* set the new root user in the credentials under preparation */ - ns->creator = new->user; new->user = root_user; new->uid = new->euid = new->suid = new->fsuid = 0; new->gid = new->egid = new->sgid = new->fsgid = 0; @@ -69,7 +64,6 @@ static void free_user_ns_work(struct work_struct *work) { struct user_namespace *ns = container_of(work, struct user_namespace, destroyer); - free_uid(ns->creator); kfree(ns); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/