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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 7ED90C433B4 for ; Sat, 15 May 2021 20:51:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53C516127A for ; Sat, 15 May 2021 20:51:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235032AbhEOUwp (ORCPT ); Sat, 15 May 2021 16:52:45 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:50161 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234987AbhEOUwj (ORCPT ); Sat, 15 May 2021 16:52:39 -0400 Received: from cpc154979-craw9-2-0-cust193.16-3.cable.virginm.net ([80.193.200.194] helo=[192.168.0.210]) by youngberry.canonical.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1li1Fr-0001mr-TT; Sat, 15 May 2021 20:51:23 +0000 Subject: Re: [PATCH-next] x86/kernel: Fix unchecked return value To: Borislav Petkov , Khaled ROMDHANI Cc: peterz@infradead.org, jpoimboe@redhat.com, jbaron@akamai.com, rostedt@goodmis.org, ardb@kernel.org, tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org References: <20210515202212.24836-1-khaledromdhani216@gmail.com> From: Colin Ian King Message-ID: <6f149c2e-eeb0-6b50-2b54-a56ae4646ea5@canonical.com> Date: Sat, 15 May 2021 21:51:23 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/05/2021 21:36, Borislav Petkov wrote: > On Sat, May 15, 2021 at 09:22:12PM +0100, Khaled ROMDHANI wrote: >> From the coverity scan analysis, the return value from >> insn_decode_kernel is not checked. It is a macro constructed >> from the insn_decode function which may fail and return >> negative integer. Fix this by explicitly checking the >> return value. >> >> Addresses-Coverity: ("Unchecked return value") >> Signed-off-by: Khaled ROMDHANI >> --- >> arch/x86/kernel/jump_label.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c >> index a762dc1c615e..bf0ea003b6e7 100644 >> --- a/arch/x86/kernel/jump_label.c >> +++ b/arch/x86/kernel/jump_label.c >> @@ -23,7 +23,7 @@ int arch_jump_entry_size(struct jump_entry *entry) >> { >> struct insn insn = {}; >> >> - insn_decode_kernel(&insn, (void *)jump_entry_code(entry)); >> + WARN_ON(insn_decode_kernel(&insn, (void *)jump_entry_code(entry))); > > I don't think coverity is smart enough to notice... > >> BUG_ON(insn.length != 2 && insn.length != 5); > ^^^^^^^^^^^^^ > > ... this line. > > Indeed. One needs to be careful with false positives with Coverity. Colin