From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35F88C43603 for ; Fri, 20 Dec 2019 12:53:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 163E22146E for ; Fri, 20 Dec 2019 12:53:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727464AbfLTMxR (ORCPT ); Fri, 20 Dec 2019 07:53:17 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:14422 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727391AbfLTMxQ (ORCPT ); Fri, 20 Dec 2019 07:53:16 -0500 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xBKCp5jD052353 for ; Fri, 20 Dec 2019 07:53:15 -0500 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2x0xccrp0m-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 20 Dec 2019 07:53:15 -0500 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 20 Dec 2019 12:53:09 -0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xBKCr8eo31457450 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 20 Dec 2019 12:53:08 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5DD0AA4054; Fri, 20 Dec 2019 12:53:08 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 201F0A4060; Fri, 20 Dec 2019 12:53:07 +0000 (GMT) Received: from localhost.localdomain (unknown [9.85.154.31]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 20 Dec 2019 12:53:07 +0000 (GMT) Subject: Re: [PATCH v5 1/2] IMA: Define workqueue for early boot "key" measurements From: Mimi Zohar To: Lakshmi Ramasubramanian , James.Bottomley@HansenPartnership.com, linux-integrity@vger.kernel.org Cc: eric.snowberg@oracle.com, dhowells@redhat.com, mathew.j.martineau@linux.intel.com, matthewgarrett@google.com, sashal@kernel.org, jamorris@linux.microsoft.com, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org Date: Fri, 20 Dec 2019 07:53:06 -0500 In-Reply-To: <503845c9-beeb-b520-ec3f-af5fa7d2b91f@linux.microsoft.com> References: <20191218164434.2877-1-nramas@linux.microsoft.com> <20191218164434.2877-2-nramas@linux.microsoft.com> <1576761104.4579.426.camel@linux.ibm.com> <503845c9-beeb-b520-ec3f-af5fa7d2b91f@linux.microsoft.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19122012-0028-0000-0000-000003CA9DAE X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19122012-0029-0000-0000-0000248DF269 Message-Id: <1576846386.5241.13.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-12-20_02:2019-12-17,2019-12-20 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 mlxscore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1015 phishscore=0 suspectscore=0 impostorscore=0 adultscore=0 mlxlogscore=999 spamscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1912200102 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Thu, 2019-12-19 at 08:55 -0800, Lakshmi Ramasubramanian wrote: > I am not sure if the mutex can be removed. > > In ima_queue_key() we need to test the flag and add the key to the list > as an atomic operation: > > if (!test_bit()) > insert_key_to_list > > Suppose the if condition is true, but before we could insert the key to > the list, ima_process_queued_keys() runs and processes queued keys we'll > add the key to the list and never process it. > > Is there an API in the kernel to test and add an entry to a list > atomically? Ok, using test_and_set_bit() and test_bit() only helps, if we can get rid of the mutex.  I'll queue these patches. thanks, Mimi