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=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,USER_AGENT_GIT autolearn=unavailable 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 96A38C28EBD for ; Sun, 9 Jun 2019 17:03:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 66D1120840 for ; Sun, 9 Jun 2019 17:03:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560099789; bh=v8jViTz1Qm/qg5OtQF+8F/At7QLvjzJgBcP9xOl6joc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PIXjr988UbPCRdHILziynD8zxAw/TID7y7LBm2UHorw1cA8pPGCV1J1agl0HtXbuy pPwMTQdGpvmNFVsb2nP9H1o9m7JBSuOyn0DCMkdihn3XrpmQt4MIsc9CMxwlH0ckE+ LnAaYw+XsaEbpOk5NnaTG1OkFzlILjaSgyR9Z28s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388361AbfFIRDI (ORCPT ); Sun, 9 Jun 2019 13:03:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:41314 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732837AbfFIRDD (ORCPT ); Sun, 9 Jun 2019 13:03:03 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A836220843; Sun, 9 Jun 2019 17:03:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560099783; bh=v8jViTz1Qm/qg5OtQF+8F/At7QLvjzJgBcP9xOl6joc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jche9IaP6For1VhF8Wgz3KT/TDyCPUqymMMMQC9177ffj3tM1lCl1KULJUay2CECC aBRRQaGi36uW5hhqnhOoGgPPpq6/4R6Xj6QohCrvDGB3Ab3DEj61ntuNn5ejGJCdbm szsb5p4vD60sMBaAUQXlGFojl/Y4pOgU4TXpMxAo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Gustavo A. R. Silva" , "David S. Miller" , Sasha Levin Subject: [PATCH 4.4 164/241] cxgb3/l2t: Fix undefined behaviour Date: Sun, 9 Jun 2019 18:41:46 +0200 Message-Id: <20190609164152.508267997@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190609164147.729157653@linuxfoundation.org> References: <20190609164147.729157653@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 76497732932f15e7323dc805e8ea8dc11bb587cf ] The use of zero-sized array causes undefined behaviour when it is not the last member in a structure. As it happens to be in this case. Also, the current code makes use of a language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as this one is a flexible array member, introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last. Which is beneficial to cultivate a high-quality code. Fixes: e48f129c2f20 ("[SCSI] cxgb3i: convert cdev->l2opt to use rcu to prevent NULL dereference") Signed-off-by: Gustavo A. R. Silva Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/chelsio/cxgb3/l2t.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/chelsio/cxgb3/l2t.h b/drivers/net/ethernet/chelsio/cxgb3/l2t.h index 8cffcdfd56782..38b5858c335a9 100644 --- a/drivers/net/ethernet/chelsio/cxgb3/l2t.h +++ b/drivers/net/ethernet/chelsio/cxgb3/l2t.h @@ -75,8 +75,8 @@ struct l2t_data { struct l2t_entry *rover; /* starting point for next allocation */ atomic_t nfree; /* number of free entries */ rwlock_t lock; - struct l2t_entry l2tab[0]; struct rcu_head rcu_head; /* to handle rcu cleanup */ + struct l2t_entry l2tab[]; }; typedef void (*arp_failure_handler_func)(struct t3cdev * dev, -- 2.20.1