From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zhong Subject: Re: [RFC PATCH next] fix unpaired rcu lock in prepend_path() Date: Thu, 14 Nov 2013 10:17:51 +0800 Message-ID: <1384395471.2497.6.camel@ThinkPad-T5421> References: <1384327311.19669.8.camel@ThinkPad-T5421> <20131113122848.GZ13318@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from e23smtp06.au.ibm.com ([202.81.31.148]:51456 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750895Ab3KNCR7 (ORCPT ); Wed, 13 Nov 2013 21:17:59 -0500 Received: from /spool/local by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 14 Nov 2013 12:17:57 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 966082BB0055 for ; Thu, 14 Nov 2013 13:17:55 +1100 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id rAE20Fn466584710 for ; Thu, 14 Nov 2013 13:00:16 +1100 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id rAE2Hs7N024508 for ; Thu, 14 Nov 2013 13:17:54 +1100 In-Reply-To: <20131113122848.GZ13318@ZenIV.linux.org.uk> Sender: linux-next-owner@vger.kernel.org List-ID: To: Al Viro Cc: linux-next list On Wed, 2013-11-13 at 12:28 +0000, Al Viro wrote: > On Wed, Nov 13, 2013 at 03:21:51PM +0800, Li Zhong wrote: > > The patch tries to fix following complaint(next-1112) caused by unpaired > > rcu_read_lock/unlock in function prepend_path(): > > Frankly, I wonder if it wouldn't be better to shift rcu_read_unlock() > past the second done_seqretry() in there... Do you mean we have rcu_read_lock/unlock outside of the goto loops? It seems to me it would cause the two locks(mount,rename) potentially acquired inside rcu read lock. Or did I misunderstand something here? Thanks, Zhong >