From patchwork Thu Jun 23 02:37:56 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joonsoo Kim X-Patchwork-Id: 9194403 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 62DB7601C0 for ; Thu, 23 Jun 2016 02:37:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 48B352841D for ; Thu, 23 Jun 2016 02:37:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3AF902842C; Thu, 23 Jun 2016 02:37:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id ABA272841D for ; Thu, 23 Jun 2016 02:37:13 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bFuUc-0001pv-UH; Thu, 23 Jun 2016 02:35:46 +0000 Received: from lgeamrelo12.lge.com ([156.147.23.52]) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bFuUZ-0001bu-Dp for linux-arm-kernel@lists.infradead.org; Thu, 23 Jun 2016 02:35:45 +0000 Received: from unknown (HELO lgemrelse6q.lge.com) (156.147.1.121) by 156.147.23.52 with ESMTP; 23 Jun 2016 11:35:19 +0900 X-Original-SENDERIP: 156.147.1.121 X-Original-MAILFROM: iamjoonsoo.kim@lge.com Received: from unknown (HELO localhost) (10.177.222.138) by 156.147.1.121 with ESMTP; 23 Jun 2016 11:35:19 +0900 X-Original-SENDERIP: 10.177.222.138 X-Original-MAILFROM: iamjoonsoo.kim@lge.com Date: Thu, 23 Jun 2016 11:37:56 +0900 From: Joonsoo Kim To: "Paul E. McKenney" Subject: Re: Boot failure on emev2/kzm9d (was: Re: [PATCH v2 11/11] mm/slab: lockless decision to grow cache) Message-ID: <20160623023756.GA30438@js1304-P5Q-DELUXE> References: <20160615022325.GA19863@js1304-P5Q-DELUXE> <20160620063942.GA13747@js1304-P5Q-DELUXE> <20160620131254.GO3923@linux.vnet.ibm.com> <20160621064302.GA20635@js1304-P5Q-DELUXE> <20160621125406.GF3923@linux.vnet.ibm.com> <20160622005208.GB25106@js1304-P5Q-DELUXE> <20160622190859.GA1473@linux.vnet.ibm.com> <20160623004935.GA20752@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20160623004935.GA20752@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160622_193543_820746_FC486264 X-CRM114-Status: GOOD ( 26.24 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-renesas-soc@vger.kernel.org, David Rientjes , "linux-kernel@vger.kernel.org" , Pekka Enberg , Linux MM , Geert Uytterhoeven , Jesper Dangaard Brouer , Andrew Morton , Christoph Lameter , "linux-arm-kernel@lists.infradead.org" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP On Wed, Jun 22, 2016 at 05:49:35PM -0700, Paul E. McKenney wrote: > On Wed, Jun 22, 2016 at 12:08:59PM -0700, Paul E. McKenney wrote: > > On Wed, Jun 22, 2016 at 05:01:35PM +0200, Geert Uytterhoeven wrote: > > > On Wed, Jun 22, 2016 at 2:52 AM, Joonsoo Kim wrote: > > > > Could you try below patch to check who causes the hang? > > > > > > > > And, if sysalt-t works when hang, could you get sysalt-t output? I haven't > > > > used it before but Paul could find some culprit on it. :) > > > > > > > > Thanks. > > > > > > > > > > > > ----->8----- > > > > diff --git a/mm/slab.c b/mm/slab.c > > > > index 763096a..9652d38 100644 > > > > --- a/mm/slab.c > > > > +++ b/mm/slab.c > > > > @@ -964,8 +964,13 @@ static int setup_kmem_cache_node(struct kmem_cache *cachep, > > > > * guaranteed to be valid until irq is re-enabled, because it will be > > > > * freed after synchronize_sched(). > > > > */ > > > > - if (force_change) > > > > + if (force_change) { > > > > + if (num_online_cpus() > 1) > > > > + dump_stack(); > > > > synchronize_sched(); > > > > + if (num_online_cpus() > 1) > > > > + dump_stack(); > > > > + } > > > > > > I've only added the first one, as I would never see the second one. All of > > > this happens before the serial console is activated, earlycon is not supported, > > > and I only have remote access. > > > > > > Brought up 2 CPUs > > > SMP: Total of 2 processors activated (2132.00 BogoMIPS). > > > CPU: All CPU(s) started in SVC mode. > > > CPU: 0 PID: 1 Comm: swapper/0 Not tainted > > > 4.7.0-rc4-kzm9d-00404-g4a235e6dde4404dd-dirty #89 > > > Hardware name: Generic Emma Mobile EV2 (Flattened Device Tree) > > > [] (unwind_backtrace) from [] (show_stack+0x10/0x14) > > > [] (show_stack) from [] (dump_stack+0x7c/0x9c) > > > [] (dump_stack) from [] (setup_kmem_cache_node+0x140/0x170) > > > [] (setup_kmem_cache_node) from [] > > > (__do_tune_cpucache+0xf4/0x114) > > > [] (__do_tune_cpucache) from [] (enable_cpucache+0xf8/0x148) > > > [] (enable_cpucache) from [] > > > (__kmem_cache_create+0x1a8/0x1d0) > > > [] (__kmem_cache_create) from [] > > > (kmem_cache_create+0xbc/0x190) > > > [] (kmem_cache_create) from [] (shmem_init+0x34/0xb0) > > > [] (shmem_init) from [] (kernel_init_freeable+0x98/0x1ec) > > > [] (kernel_init_freeable) from [] (kernel_init+0x8/0x110) > > > [] (kernel_init) from [] (ret_from_fork+0x14/0x3c) > > > devtmpfs: initialized > > > > I don't see anything here that would prevent grace periods from completing. > > > > The CPUs are using the normal hotplug sequence to come online, correct? > > And either way, could you please apply the patch below and then > invoke rcu_dump_rcu_sched_tree() just before the offending call to > synchronize_sched()? That will tell me what CPUs RCU believes exist, > and perhaps also which CPU is holding it up. I can't find rcu_dump_rcu_sched_tree(). Do you mean rcu_dump_rcu_node_tree()? Anyway, there is no patch below so I attach one which does what Paul want, maybe. Thanks. ------->8--------- diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 88d3f95..6b650f0 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4171,7 +4171,7 @@ static void __init rcu_init_geometry(void) * Dump out the structure of the rcu_node combining tree associated * with the rcu_state structure referenced by rsp. */ -static void __init rcu_dump_rcu_node_tree(struct rcu_state *rsp) +static void rcu_dump_rcu_node_tree(struct rcu_state *rsp) { int level = 0; struct rcu_node *rnp; @@ -4189,6 +4189,11 @@ static void __init rcu_dump_rcu_node_tree(struct rcu_state *rsp) pr_cont("\n"); } +void rcu_dump_rcu_sched_tree(void) +{ + rcu_dump_rcu_node_tree(&rcu_sched_state); +} + void __init rcu_init(void) { int cpu; diff --git a/mm/slab.c b/mm/slab.c index 763096a..d88976c 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -909,6 +909,8 @@ static int init_cache_node_node(int node) return 0; } +extern void rcu_dump_rcu_sched_tree(void); + static int setup_kmem_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp, bool force_change) { @@ -964,8 +966,10 @@ static int setup_kmem_cache_node(struct kmem_cache *cachep, * guaranteed to be valid until irq is re-enabled, because it will be * freed after synchronize_sched(). */ - if (force_change) + if (force_change) { + rcu_dump_rcu_sched_tree(); synchronize_sched(); + } fail: kfree(old_shared);