From patchwork Sat Sep 11 02:29:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Christopher M. Riedl" X-Patchwork-Id: 12537667 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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8A982C433EF for ; Sat, 11 Sep 2021 02:29:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6122E611CC for ; Sat, 11 Sep 2021 02:29:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235149AbhIKCak (ORCPT ); Fri, 10 Sep 2021 22:30:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231864AbhIKCaj (ORCPT ); Fri, 10 Sep 2021 22:30:39 -0400 Received: from mout-p-102.mailbox.org (mout-p-102.mailbox.org [IPv6:2001:67c:2050::465:102]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07A43C061574 for ; Fri, 10 Sep 2021 19:29:27 -0700 (PDT) Received: from smtp102.mailbox.org (smtp102.mailbox.org [80.241.60.233]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-102.mailbox.org (Postfix) with ESMTPS id 4H5xX5662jzQk95; Sat, 11 Sep 2021 04:29:25 +0200 (CEST) X-Virus-Scanned: amavisd-new at heinlein-support.de From: "Christopher M. Riedl" To: linuxppc-dev@lists.ozlabs.org Cc: linux-hardening@vger.kernel.org Subject: [PATCH v6 3/4] powerpc: Use WARN_ON and fix check in poking_init Date: Fri, 10 Sep 2021 21:29:03 -0500 Message-Id: <20210911022904.30962-4-cmr@bluescreens.de> In-Reply-To: <20210911022904.30962-1-cmr@bluescreens.de> References: <20210911022904.30962-1-cmr@bluescreens.de> MIME-Version: 1.0 X-Rspamd-Queue-Id: 9DE9826E Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org The latest kernel docs list BUG_ON() as 'deprecated' and that they should be replaced with WARN_ON() (or pr_warn()) when possible. The BUG_ON() in poking_init() warrants a WARN_ON() rather than a pr_warn() since the error condition is deemed "unreachable". Also take this opportunity to fix the failure check in the WARN_ON(): cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, ...) returns a positive integer on success and a negative integer on failure. Signed-off-by: Christopher M. Riedl --- v6: * New to series - based on Christophe's relentless feedback in the crusade against BUG_ON()s :) --- arch/powerpc/lib/code-patching.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 8d0bb86125d5..e802e42c2789 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -126,16 +126,11 @@ static int text_area_cpu_down(unsigned int cpu) return 0; } -/* - * Although BUG_ON() is rude, in this case it should only happen if ENOMEM, and - * we judge it as being preferable to a kernel that will crash later when - * someone tries to use patch_instruction(). - */ void __init poking_init(void) { - BUG_ON(!cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, + WARN_ON(cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/text_poke:online", text_area_cpu_up, - text_area_cpu_down)); + text_area_cpu_down) < 0); } /*