From patchwork Sun Nov 4 01:05:58 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10666811 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 93EE817DB for ; Sun, 4 Nov 2018 01:17:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 70AD92928B for ; Sun, 4 Nov 2018 01:17:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 604D429BBC; Sun, 4 Nov 2018 01:17:49 +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 ECC0F2928B for ; Sun, 4 Nov 2018 01:17:48 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 9332321A00AE6; Sat, 3 Nov 2018 18:17:48 -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=192.55.52.43; helo=mga05.intel.com; envelope-from=dan.j.williams@intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (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 487C22115C33C for ; Sat, 3 Nov 2018 18:17:47 -0700 (PDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Nov 2018 18:17:46 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,462,1534834800"; d="scan'208";a="271168550" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga005.jf.intel.com with ESMTP; 03 Nov 2018 18:17:46 -0700 Subject: [PATCH] Revert "acpi, nfit: Further restrict userspace ARS start requests" From: Dan Williams To: linux-nvdimm@lists.01.org Date: Sat, 03 Nov 2018 18:05:58 -0700 Message-ID: <154129355792.421728.127261092571335116.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: , Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP The following lockdep splat results from acquiring the init_mutex in acpi_nfit_clear_to_send(): WARNING: possible circular locking dependency detected lt-daxdev-error/7216 is trying to acquire lock: 00000000f694db15 (&acpi_desc->init_mutex){+.+.}, at: acpi_nfit_clear_to_send+0x27/0x80 [nfit] but task is already holding lock: 00000000182298f2 (&nvdimm_bus->reconfig_mutex){+.+.}, at: __nd_ioctl+0x457/0x610 [libnvdimm] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&nvdimm_bus->reconfig_mutex){+.+.}: nvdimm_badblocks_populate+0x41/0x150 [libnvdimm] nd_region_notify+0x95/0xb0 [libnvdimm] nd_device_notify+0x40/0x50 [libnvdimm] ars_complete+0x7f/0xd0 [nfit] acpi_nfit_scrub+0xbb/0x410 [nfit] process_one_work+0x22b/0x5c0 worker_thread+0x3c/0x390 kthread+0x11e/0x140 ret_from_fork+0x3a/0x50 -> #0 (&acpi_desc->init_mutex){+.+.}: __mutex_lock+0x83/0x980 acpi_nfit_clear_to_send+0x27/0x80 [nfit] __nd_ioctl+0x474/0x610 [libnvdimm] nd_ioctl+0xa4/0xb0 [libnvdimm] do_vfs_ioctl+0xa5/0x6e0 ksys_ioctl+0x70/0x80 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x60/0x210 entry_SYSCALL_64_after_hwframe+0x49/0xbe New infrastructure is needed to be able to perform this check without acquiring the lock. Fixes: 594861215c83 ("acpi, nfit: Further restrict userspace ARS start") Cc: Dave Jiang Signed-off-by: Dan Williams --- drivers/acpi/nfit/core.c | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 5970b8f5f768..14d9f5bea015 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -3341,8 +3341,6 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm, unsigned int cmd) { struct acpi_nfit_desc *acpi_desc = to_acpi_nfit_desc(nd_desc); - struct nfit_spa *nfit_spa; - int rc = 0; if (nvdimm) return 0; @@ -3355,17 +3353,10 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc, * just needs guarantees that any ARS it initiates are not * interrupted by any intervening start requests from userspace. */ - mutex_lock(&acpi_desc->init_mutex); - list_for_each_entry(nfit_spa, &acpi_desc->spas, list) - if (acpi_desc->scrub_spa - || test_bit(ARS_REQ_SHORT, &nfit_spa->ars_state) - || test_bit(ARS_REQ_LONG, &nfit_spa->ars_state)) { - rc = -EBUSY; - break; - } - mutex_unlock(&acpi_desc->init_mutex); + if (work_busy(&acpi_desc->dwork.work)) + return -EBUSY; - return rc; + return 0; } int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc,