Return-Path: Received: from mail-qt0-f174.google.com ([209.85.216.174]:45083 "EHLO mail-qt0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751415AbdJJRTX (ORCPT ); Tue, 10 Oct 2017 13:19:23 -0400 Date: Tue, 10 Oct 2017 10:19:19 -0700 From: "tj@kernel.org" To: Trond Myklebust Cc: "bfields@fieldses.org" , "linux-kernel@vger.kernel.org" , "lorenzo.pieralisi@arm.com" , "jlayton@poochiereds.net" , "linux-nfs@vger.kernel.org" , "jiangshanlai@gmail.com" , "anna.schumaker@netapp.com" Subject: Re: net/sunrpc: v4.14-rc4 lockdep warning Message-ID: <20171010171919.GO3301751@devbig577.frc2.facebook.com> References: <20171009181738.GA30680@red-moon> <1507573931.3516.3.camel@primarydata.com> <20171010140336.GI3301751@devbig577.frc2.facebook.com> <1507654135.4442.4.camel@primarydata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1507654135.4442.4.camel@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Hello, On Tue, Oct 10, 2017 at 04:48:57PM +0000, Trond Myklebust wrote: > Thanks for the explanation. What I'm not really understanding here > though, is how the work item could be queued at all. We have a > wait_on_bit_lock() in xprt_destroy() that should mean the xprt- > >task_cleanup work item has completed running, and that it cannot be > requeued. > > Is there a possibility that the flush_queue() might be triggered > despite the work item not being queued? Yeah, for sure. The lockdep annotations don't distinguish those cases and assume the worst case. Thanks. -- tejun