From patchwork Thu Jul 18 01:07:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 11048347 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EB1156C5 for ; Thu, 18 Jul 2019 01:22:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DB16E286CB for ; Thu, 18 Jul 2019 01:22:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CEC4828796; Thu, 18 Jul 2019 01:22:09 +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=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id B8B41286CB for ; Thu, 18 Jul 2019 01:22:08 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id BE331212C01CF; Wed, 17 Jul 2019 18:24:36 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=134.134.136.126; helo=mga18.intel.com; envelope-from=dan.j.williams@intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 9B070212BF9DE for ; Wed, 17 Jul 2019 18:24:33 -0700 (PDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Jul 2019 18:22:04 -0700 X-IronPort-AV: E=Sophos;i="5.64,276,1559545200"; d="scan'208";a="170424120" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Jul 2019 18:22:05 -0700 Subject: [PATCH v2 0/7] libnvdimm: Fix async operations and locking From: Dan Williams To: linux-nvdimm@lists.01.org Date: Wed, 17 Jul 2019 18:07:48 -0700 Message-ID: <156341206785.292348.1660822720191643298.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Rafael J. Wysocki" , "Rafael J. Wysocki" , Peter Zijlstra , Greg Kroah-Hartman , Will Deacon , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Ingo Molnar , Erwin Tsaur Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP Changes since v1 [1]: - Fix an ioctl command corruption regression that manifested as an intermittent failure of the monitor.sh unit test. This is handled in the patch4 prep patch that makes it safe for nd_ioctl() to be re-entrant. (Vishal) - Update the changelog for the driver-core 'lockdep_lock' hack to indicate Greg's non-NAK. [1]: https://lore.kernel.org/lkml/156029554317.419799.1324389595953183385.stgit@dwillia2-desk3.amr.corp.intel.com/ --- The libnvdimm subsystem uses async operations to parallelize device probing operations and to allow sysfs to trigger device_unregister() on deleted namepsaces. A multithreaded stress test of the libnvdimm sysfs interface uncovered a case where device_unregister() is triggered multiple times, and the subsequent investigation uncovered a broken locking scenario. The lack of lockdep coverage for device_lock() stymied the debug. That is, until patch6 "driver-core, libnvdimm: Let device subsystems add local lockdep coverage" solved that with a shadow lock, with lockdep coverage, to mirror device_lock() operations. Given the time saved with shadow-lock debug-hack, patch6 attempts to generalize device_lock() debug facility that might be able to be carried upstream. Patch6 is staged at the end of this fix series in case it is contentious and needs to be dropped. Patch1 "drivers/base: Introduce kill_device()" could be achieved with local libnvdimm infrastructure. However, the existing 'dead' flag in 'struct device_private' aims to solve similar async register/unregister races so the fix in patch2 "libnvdimm/bus: Prevent duplicate device_unregister() calls" can be implemented with existing driver-core infrastructure. Patch3 is a rare lockdep warning that is intermittent based on namespaces racing ahead of the completion of probe of their parent region. It is not related to the other fixes, it just happened to trigger as a result of the async stress test. Patch5 and patch6 address an ABBA deadlock tripped by the stress test. These patches pass the failing stress test and the existing libnvdimm unit tests with CONFIG_PROVE_LOCKING=y and the new "dev->lockdep_mutex" shadow lock with no lockdep warnings. --- Dan Williams (7): drivers/base: Introduce kill_device() libnvdimm/bus: Prevent duplicate device_unregister() calls libnvdimm/region: Register badblocks before namespaces libnvdimm/bus: Prepare the nd_ioctl() path to be re-entrant libnvdimm/bus: Stop holding nvdimm_bus_list_mutex over __nd_ioctl() libnvdimm/bus: Fix wait_nvdimm_bus_probe_idle() ABBA deadlock driver-core, libnvdimm: Let device subsystems add local lockdep coverage drivers/acpi/nfit/core.c | 28 +++-- drivers/acpi/nfit/nfit.h | 24 ++++ drivers/base/core.c | 30 ++++-- drivers/nvdimm/btt_devs.c | 16 +-- drivers/nvdimm/bus.c | 210 ++++++++++++++++++++++++++------------- drivers/nvdimm/core.c | 10 +- drivers/nvdimm/dimm_devs.c | 4 - drivers/nvdimm/namespace_devs.c | 36 +++---- drivers/nvdimm/nd-core.h | 71 +++++++++++++ drivers/nvdimm/pfn_devs.c | 24 ++-- drivers/nvdimm/pmem.c | 4 - drivers/nvdimm/region.c | 24 ++-- drivers/nvdimm/region_devs.c | 12 +- include/linux/device.h | 6 + 14 files changed, 343 insertions(+), 156 deletions(-)