From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([65.50.211.133]:33376 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751332AbdB1IOY (ORCPT ); Tue, 28 Feb 2017 03:14:24 -0500 Date: Tue, 28 Feb 2017 08:48:02 +0100 From: Peter Zijlstra To: Fengguang Wu Cc: linux-block , Omar Sandoval , Jens Axboe , LKP Subject: Re: [blk_mq_register_hctx] 29dee3c03a WARNING: CPU: 0 PID: 5 at lib/refcount.c:114 refcount_inc Message-ID: <20170228074802.GC6500@twins.programming.kicks-ass.net> References: <20170228041117.hbqqyczf5bnypqmc@wfg-t540p.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20170228041117.hbqqyczf5bnypqmc@wfg-t540p.sh.intel.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Tue, Feb 28, 2017 at 12:11:17PM +0800, Fengguang Wu wrote: > Hello, > > FYI, an old blk_mq bug triggers new warnings on this commit. It's very > reproducible and you may try the attached reproduce-* script. > > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > commit 29dee3c03abce04cd527878ef5f9e5f91b7b83f4 > Author: Peter Zijlstra > AuthorDate: Fri Feb 10 16:27:52 2017 +0100 > Commit: Ingo Molnar > CommitDate: Fri Feb 24 09:02:10 2017 +0100 > > locking/refcounts: Out-of-line everything > > Linus asked to please make this real C code. > > And since size then isn't an issue what so ever anymore, remove the > debug knob and make all WARN()s unconditional. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ I suspect that if you revert, but enable CONFIG_DEBUG_REFCOUNT you'd have gotten the same splats.. I'll go have a look though, something looks buggered.