From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964897AbcHDOcL (ORCPT ); Thu, 4 Aug 2016 10:32:11 -0400 Received: from mail-by2nam01on0087.outbound.protection.outlook.com ([104.47.34.87]:60043 "EHLO NAM01-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758683AbcHDOcI (ORCPT ); Thu, 4 Aug 2016 10:32:08 -0400 Authentication-Results: spf=pass (sender IP is 63.163.107.21) smtp.mailfrom=sandisk.com; infradead.org; dkim=none (message not signed) header.d=none;infradead.org; dmarc=bestguesspass action=none header.from=sandisk.com; X-AuditID: ac160c69-5dfff70000000bcb-a6-57a35001490d Subject: Re: [PATCH] sched: Avoid that __wait_on_bit_lock() hangs To: Peter Zijlstra References: <20160803181128.GH6879@twins.programming.kicks-ass.net> <11007730-3fa5-139a-8091-655743894ae8@sandisk.com> <20160803213006.GA11712@redhat.com> <17b65ff9-215f-ab74-9f5f-15dbd308d054@sandisk.com> <20160804140938.GB24652@twins.programming.kicks-ass.net> CC: Oleg Nesterov , "mingo@kernel.org" , Andrew Morton , Johannes Weiner , Neil Brown , Michael Shaver , "linux-kernel@vger.kernel.org" From: Bart Van Assche Message-ID: <8003deba-7190-8a05-aa81-2b76f0643756@sandisk.com> Date: Thu, 4 Aug 2016 07:31:48 -0700 User-Agent: Mozilla/5.0 (X11; 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What are you > doing to reproduce this issue? Hello Peter, The test I run is as follows: * Configure the ib_srpt driver to export a RAM disk through the SRP protocol. The ib_srpt driver is a LIO target driver that implements the SRP protocol, a SCSI transport protocol. * On the same system, let the ib_srp (SRP initiator) driver log in to the ib_srpt driver using the loopback capability of a local InfiniBand HCA. * Run fio with data verification enabled on top of multipath (dm-mpath) with queue_if_no_path enabled and let multipath use the SRP paths. * Simulate cable pulls and reinserts by periodically writing in the /sys/class/srp_remote_ports/*/delete and by logging in again. Writing into the delete attribute triggers scsi_remove_host() and hence also removal of the block device associated with the SCSI device. The scripts I use to run this test are available at https://github.com/bvanassche/srp-test. Since the softRoCE driver is not yet upstream running this test requires at least one InfiniBand HCA. Thanks, Bart.