From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Triplett Subject: Re: What does this sparse warning mean in posix_acl.h? Date: Sat, 17 Aug 2013 09:17:18 -0700 Message-ID: <20130817161718.GA18897@leaf> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from relay4-d.mail.gandi.net ([217.70.183.196]:47637 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753444Ab3HQQR1 (ORCPT ); Sat, 17 Aug 2013 12:17:27 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: Theodore Ts'o Cc: linux-fsdevel@vger.kernel.org, linux-sparse@vger.kernel.org On Sat, Aug 17, 2013 at 10:28:22AM -0400, Theodore Ts'o wrote: > It apparently has something to do with rcu and "address spaces" but I'm > not completely sure what sparse is complaining about --- and whether it > is a false positive or a bug in the posix_acl.h. > > Can someone explain what's going on, and whether it's something to be > concerned about? [...] > /usr/projects/linux/ext4/include/linux/posix_acl.h:137:9: warning: incorrect type in assignment (different address spaces) > /usr/projects/linux/ext4/include/linux/posix_acl.h:137:9: expected struct posix_acl * > /usr/projects/linux/ext4/include/linux/posix_acl.h:137:9: got struct posix_acl [noderef] * > /usr/projects/linux/ext4/include/linux/posix_acl.h:137:9: warning: incorrect type in assignment (different address spaces) > /usr/projects/linux/ext4/include/linux/posix_acl.h:137:9: expected struct posix_acl * > /usr/projects/linux/ext4/include/linux/posix_acl.h:137:9: got struct posix_acl [noderef] * Address space 4 is __rcu. This warning means you accessed an RCU pointer directly, without using the appropriate RCU primitive (rcu_assign_pointer, rcu_dereference, etc). - Josh Triplett