From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752469AbdHILmU (ORCPT ); Wed, 9 Aug 2017 07:42:20 -0400 Received: from foss.arm.com ([217.140.101.70]:46580 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751942AbdHILmT (ORCPT ); Wed, 9 Aug 2017 07:42:19 -0400 Date: Wed, 9 Aug 2017 12:42:13 +0100 From: Marc Zyngier To: YASUAKI ISHIMATSU Cc: tglx@linutronix.de, axboe@kernel.dk, mpe@ellerman.id.au, keith.busch@intel.com, peterz@infradead.org, LKML Subject: Re: system hung up when offlining CPUs Message-ID: <20170809124213.0d9518bb@why.wild-wind.fr.eu.org> In-Reply-To: References: Organization: ARM Ltd X-Mailer: Claws Mail 3.14.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 8 Aug 2017 15:25:35 -0400 YASUAKI ISHIMATSU wrote: > Hi Thomas, > > When offlining all CPUs except cpu0, system hung up with the following message. > > [...] INFO: task kworker/u384:1:1234 blocked for more than 120 seconds. > [...] Not tainted 4.12.0-rc6+ #19 > [...] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [...] kworker/u384:1 D 0 1234 2 0x00000000 > [...] Workqueue: writeback wb_workfn (flush-253:0) > [...] Call Trace: > [...] __schedule+0x28a/0x880 > [...] schedule+0x36/0x80 > [...] schedule_timeout+0x249/0x300 > [...] ? __schedule+0x292/0x880 > [...] __down_common+0xfc/0x132 > [...] ? _xfs_buf_find+0x2bb/0x510 [xfs] > [...] __down+0x1d/0x1f > [...] down+0x41/0x50 > [...] xfs_buf_lock+0x3c/0xf0 [xfs] > [...] _xfs_buf_find+0x2bb/0x510 [xfs] > [...] xfs_buf_get_map+0x2a/0x280 [xfs] > [...] xfs_buf_read_map+0x2d/0x180 [xfs] > [...] xfs_trans_read_buf_map+0xf5/0x310 [xfs] > [...] xfs_btree_read_buf_block.constprop.35+0x78/0xc0 [xfs] > [...] xfs_btree_lookup_get_block+0x88/0x160 [xfs] > [...] xfs_btree_lookup+0xd0/0x3b0 [xfs] > [...] ? xfs_allocbt_init_cursor+0x41/0xe0 [xfs] > [...] xfs_alloc_ag_vextent_near+0xaf/0xaa0 [xfs] > [...] xfs_alloc_ag_vextent+0x13c/0x150 [xfs] > [...] xfs_alloc_vextent+0x425/0x590 [xfs] > [...] xfs_bmap_btalloc+0x448/0x770 [xfs] > [...] xfs_bmap_alloc+0xe/0x10 [xfs] > [...] xfs_bmapi_write+0x61d/0xc10 [xfs] > [...] ? kmem_zone_alloc+0x96/0x100 [xfs] > [...] xfs_iomap_write_allocate+0x199/0x3a0 [xfs] > [...] xfs_map_blocks+0x1e8/0x260 [xfs] > [...] xfs_do_writepage+0x1ca/0x680 [xfs] > [...] write_cache_pages+0x26f/0x510 > [...] ? xfs_vm_set_page_dirty+0x1d0/0x1d0 [xfs] > [...] ? blk_mq_dispatch_rq_list+0x305/0x410 > [...] ? deadline_remove_request+0x7d/0xc0 > [...] xfs_vm_writepages+0xb6/0xd0 [xfs] > [...] do_writepages+0x1c/0x70 > [...] __writeback_single_inode+0x45/0x320 > [...] writeback_sb_inodes+0x280/0x570 > [...] __writeback_inodes_wb+0x8c/0xc0 > [...] wb_writeback+0x276/0x310 > [...] ? get_nr_dirty_inodes+0x4d/0x80 > [...] wb_workfn+0x2d4/0x3b0 > [...] process_one_work+0x149/0x360 > [...] worker_thread+0x4d/0x3c0 > [...] kthread+0x109/0x140 > [...] ? rescuer_thread+0x380/0x380 > [...] ? kthread_park+0x60/0x60 > [...] ret_from_fork+0x25/0x30 > > > I bisected upstream kernel. And I found that the following commit lead > the issue. > > commit c5cb83bb337c25caae995d992d1cdf9b317f83de > Author: Thomas Gleixner > Date: Tue Jun 20 01:37:51 2017 +0200 > > genirq/cpuhotplug: Handle managed IRQs on CPU hotplug Can you please post your /proc/interrupts and details of which interrupt you think goes wrong? This backtrace is not telling us much in terms of where to start looking... Thanks, M. -- Without deviation from the norm, progress is not possible.