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=-11.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT,USER_AGENT_SANE_1 autolearn=ham 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 53472C2BA19 for ; Mon, 6 Apr 2020 11:00:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2117B206F5 for ; Mon, 6 Apr 2020 11:00:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XKJsvcpo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727126AbgDFK77 (ORCPT ); Mon, 6 Apr 2020 06:59:59 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:44553 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726841AbgDFK77 (ORCPT ); Mon, 6 Apr 2020 06:59:59 -0400 Received: by mail-pg1-f193.google.com with SMTP id 142so7350854pgf.11; Mon, 06 Apr 2020 03:59:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=76mGlpp6BFJSmPDHJW6kprv/8C2HQ3fa7ORMT87pipU=; b=XKJsvcpo7Y3eIsvwt+slK2It9/UwJptza1whwFfWJeSj+Tk+KPPzWRnlV8RzFZnRco /y7P0QfbJX6+uyw/ECZSlNemCC0/iajDr+1ag30GCLMMRu5NcpKvX9FkOA2gYmQZI698 NHwzj58/n2FvYzGWfXQMvk+h0znA13zDb/EZuCDh94XdXGJYTJiQw0ILMoO5sLMAePcA vaAVOnzoTiiSNsWCJVKud051c87X5fZ2jUa/FtqGx2Asx2VGORgUd7wMw2XAlPwydg/+ SrGwQPAkrr9goYq8UrZDdBGT2FeBGd/7ZJLVvTxDRZwkeZhXyMGxpuHt9BOGKWHq7Xl8 N2Tg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:user-agent; bh=76mGlpp6BFJSmPDHJW6kprv/8C2HQ3fa7ORMT87pipU=; b=CmAadlBZ25hcVGYOPKOizSV9QjkVYyy+QiMBybhyUtKTNQY9ByYi6E14iw4093Y3EJ mb0WCPhQla3T32nVuKdy5TNR45XlTKgaGR9MTqCDXSZ/3WAmJO2Gr9PwXUmHj1z33fD1 HTo0G3DZKVv2YzcC7Q2YQPp2iyukKQ6x6Btuds8GlfziNNrOuxv4vgXtppGiU46M5rFW kDmQaqvzgyEz7h2013pj3BeVCAXL2yLD+VuiQ9O1dIK/QUK/0aQvtFOTzET+4SjDM1Bl TG2V5P7u+eaxuy3/9OeRMgjbYSJ4imXE2pbPdmf5skhj0keEDPTm9c15Qn1XrxHJJxVk Uh6Q== X-Gm-Message-State: AGi0PuZpjTtQr78Qz6mihnvi9fjcWvNjEPeqCXuhHTXVklRBcLrFFT6S If8gdyYjudd/jAjBk7SDWYE= X-Google-Smtp-Source: APiQypLo5R6aTgUFGFSStDUnpE8fqAAl3q8UtUXqjkfX8M/Kws53j2EaC6qi929TvME8Gj6oK+ylkg== X-Received: by 2002:a62:7911:: with SMTP id u17mr20215835pfc.305.1586170796382; Mon, 06 Apr 2020 03:59:56 -0700 (PDT) Received: from workstation-kernel-dev ([103.87.57.178]) by smtp.gmail.com with ESMTPSA id x68sm9955214pfb.5.2020.04.06.03.59.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Apr 2020 03:59:55 -0700 (PDT) Date: Mon, 6 Apr 2020 16:29:50 +0530 From: Amol Grover To: James Morris , "Serge E . Hallyn" Cc: linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, Joel Fernandes , Madhuparna Bhowmik , "Paul E . McKenney" , linux-security-module@vger.kernel.org, Amol Grover Subject: [PATCH RESEND] device_cgroup: Fix RCU list debugging warning Message-ID: <20200406105950.GA2285@workstation-kernel-dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mailer: git-send-email 2.24.1 User-Agent: Mutt/1.12.2 (2019-09-21) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: exceptions may be traversed using list_for_each_entry_rcu() outside of an RCU read side critical section BUT under the protection of decgroup_mutex. Hence add the corresponding lockdep expression to fix the following false-positive warning: [ 2.304417] ============================= [ 2.304418] WARNING: suspicious RCU usage [ 2.304420] 5.5.4-stable #17 Tainted: G E [ 2.304422] ----------------------------- [ 2.304424] security/device_cgroup.c:355 RCU-list traversed in non-reader section!! Signed-off-by: Amol Grover --- security/device_cgroup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/security/device_cgroup.c b/security/device_cgroup.c index 7d0f8f7431ff..b7da9e0970d9 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -352,7 +352,8 @@ static bool match_exception_partial(struct list_head *exceptions, short type, { struct dev_exception_item *ex; - list_for_each_entry_rcu(ex, exceptions, list) { + list_for_each_entry_rcu(ex, exceptions, list, + lockdep_is_held(&devcgroup_mutex)) { if ((type & DEVCG_DEV_BLOCK) && !(ex->type & DEVCG_DEV_BLOCK)) continue; if ((type & DEVCG_DEV_CHAR) && !(ex->type & DEVCG_DEV_CHAR)) -- 2.24.1