From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755565Ab3KLPQL (ORCPT ); Tue, 12 Nov 2013 10:16:11 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52078 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753375Ab3KLPQJ (ORCPT ); Tue, 12 Nov 2013 10:16:09 -0500 Date: Tue, 12 Nov 2013 10:15:41 -0500 From: Vivek Goyal To: Peter Zijlstra Cc: Fengguang Wu , John Stultz , Ingo Molnar , linux-kernel@vger.kernel.org, Jens Axboe , Tejun Heo Subject: Re: [seqcount] INFO: trying to register non-static key. Message-ID: <20131112151541.GD24980@redhat.com> References: <20131111012927.GA404@localhost> <20131111154551.GJ19203@twins.programming.kicks-ass.net> <20131112094147.GA32441@localhost> <20131112100140.GM5056@laptop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131112100140.GM5056@laptop.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 12, 2013 at 11:01:40AM +0100, Peter Zijlstra wrote: > On Tue, Nov 12, 2013 at 05:41:47PM +0800, Fengguang Wu wrote: > > On Mon, Nov 11, 2013 at 04:45:51PM +0100, Peter Zijlstra wrote: > > > On Mon, Nov 11, 2013 at 09:29:27AM +0800, Fengguang Wu wrote: > > > > Greetings, > > > > > > > > I got the below dmesg and the first bad commit is > > > > > > > > commit 1ca7d67cf5d5a2aef26a8d9afd789006fa098347 > > > > Author: John Stultz > > > > Date: Mon Oct 7 15:51:59 2013 -0700 > > > > > > > > seqcount: Add lockdep functionality to seqcount/seqlock structures > > > > > > > > > > > [ 4.124336] uli526x: ULi M5261/M5263 net driver, version 0.9.3 (2005-7-29) > > > > [ 4.128027] Call Trace: > > > > [ 4.128027] [<7908e744>] ? console_unlock+0x353/0x380 > > > > [ 4.128027] [<79dc7cf2>] dump_stack+0x48/0x60 > > > > [ 4.128027] [<7908953e>] __lock_acquire.isra.26+0x7e3/0xceb > > > > [ 4.128027] [<7908a1c5>] lock_acquire+0x71/0x9a > > > > [ 4.128027] [<794079aa>] ? blk_throtl_bio+0x1c3/0x485 > > > > [ 4.128027] [<7940658b>] throtl_update_dispatch_stats+0x7c/0x153 > > > > > > The below seems to compile with i386-defconfig + CONFIG_CFQ_GROUP_IOSCHED=y > > > > > > No idea if it runs properly or not; I seem to have misplaced my i386 > > > root filesystem. > > > > > > --- > > > Subject: block: Employ u64_stats_init() > > > > > > Now that seqcounts are lockdep tracked thingies, we need to properly > > > initialize them, otherwise bad stuff happens. > > > > FYI the warning is still there: > > > > /kernel/i386-randconfig-j7-11082318/d3516a7318f8e22f5462888fdf9edc8f0f128024 > > > > +-------------------------------------------------+-------+--------------+--------------+ > > | | v3.12 | 838cc7b488f8 | d3516a7318f8 | > > +-------------------------------------------------+-------+--------------+--------------+ > > | boot_successes | 129 | 0 | 0 | > > | boot_failures | 1 | 100 | 100 | > > | BUG:kernel_early_hang_without_any_printk_output | 1 | | | > > | INFO:trying_to_register_non-static_key | 0 | 100 | 100 | > > +-------------------------------------------------+-------+--------------+--------------+ > > Is that from the exact same spot as before > (throtl_update_dispatch_stats) or did we hit another one? [CC tejun] Peter, I am wondering if you have to modify blk-throtl.c too to take care of per cpu stats contained inside throtl_grp. I see that we allocate per cpu stats but don't do any initializations. static void tg_stats_alloc_fn(struct work_struct *work) { static struct tg_stats_cpu *stats_cpu; /* this fn is non-reentrant */ struct delayed_work *dwork = to_delayed_work(work); bool empty = false; alloc_stats: if (!stats_cpu) { stats_cpu = alloc_percpu(struct tg_stats_cpu); if (!stats_cpu) { /* allocation failed, try again after some time */ schedule_delayed_work(dwork, msecs_to_jiffies(10)); return; } } spin_lock_irq(&tg_stats_alloc_lock); Thanks Vivek