From patchwork Fri Jan 11 22:46:37 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Luck X-Patchwork-Id: 10760763 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 2CCF291E for ; Fri, 11 Jan 2019 22:46:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 157C42A33C for ; Fri, 11 Jan 2019 22:46:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 06B2F2A33E; Fri, 11 Jan 2019 22:46:40 +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 A9E9A2A33C for ; Fri, 11 Jan 2019 22:46:39 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 752AD211B6C21; Fri, 11 Jan 2019 14:46:39 -0800 (PST) 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=192.55.52.120; helo=mga04.intel.com; envelope-from=tony.luck@intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) (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 52486211B6C1D for ; Fri, 11 Jan 2019 14:46:37 -0800 (PST) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Jan 2019 14:46:37 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,467,1539673200"; d="scan'208";a="135141440" Received: from agluck-desk.sc.intel.com (HELO agluck-desk) ([10.3.52.160]) by fmsmga004.fm.intel.com with ESMTP; 11 Jan 2019 14:46:37 -0800 Date: Fri, 11 Jan 2019 14:46:37 -0800 From: "Luck, Tony" To: Dan Williams Subject: [PATCH] acpi/nfit: Fix race accessing memdev in nfit_get_smbios_id() Message-ID: <20190111224637.GA7300@agluck-desk> References: <47b0eaaa-ad49-5062-5f1f-fb6f79b2448d@oracle.com> <3908561D78D1C84285E8C5FCA982C28F7D4C4F61@ORSMSX110.amr.corp.intel.com> <20190111221245.GA6231@agluck-desk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) 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: linux-nvdimm Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP Possible race accessing memdev structures after dropping the mutex. Dan Williams says this could race against another thread that is doing: # echo "ACPI0012:00" > /sys/bus/acpi/drivers/nfit/unbind Reported-by: Jane Chu Signed-off-by: Tony Luck --- This time with a commit message and credit to Jane for finding it. drivers/acpi/nfit/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 011d3db19c80..22945bf803c8 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -721,6 +721,7 @@ int nfit_get_smbios_id(u32 device_handle, u16 *flags) struct acpi_nfit_memory_map *memdev; struct acpi_nfit_desc *acpi_desc; struct nfit_mem *nfit_mem; + u16 physical_id; mutex_lock(&acpi_desc_lock); list_for_each_entry(acpi_desc, &acpi_descs, list) { @@ -728,10 +729,11 @@ int nfit_get_smbios_id(u32 device_handle, u16 *flags) list_for_each_entry(nfit_mem, &acpi_desc->dimms, list) { memdev = __to_nfit_memdev(nfit_mem); if (memdev->device_handle == device_handle) { + *flags = memdev->flags; + physical_id = memdev->physical_id; mutex_unlock(&acpi_desc->init_mutex); mutex_unlock(&acpi_desc_lock); - *flags = memdev->flags; - return memdev->physical_id; + return physical_id; } } mutex_unlock(&acpi_desc->init_mutex);