From nobody Sun Apr 26 21:39:10 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E849C43334 for ; Wed, 22 Jun 2022 06:50:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351552AbiFVGuL (ORCPT ); Wed, 22 Jun 2022 02:50:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351579AbiFVGty (ORCPT ); Wed, 22 Jun 2022 02:49:54 -0400 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0654035ABA for ; Tue, 21 Jun 2022 23:49:52 -0700 (PDT) Received: from fsav412.sakura.ne.jp (fsav412.sakura.ne.jp [133.242.250.111]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 25M6nNKG065902; Wed, 22 Jun 2022 15:49:23 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav412.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav412.sakura.ne.jp); Wed, 22 Jun 2022 15:49:23 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav412.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 25M6nMAZ065894 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Wed, 22 Jun 2022 15:49:23 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: <795c9463-452e-bf64-1cc0-c318ccecb1da@I-love.SAKURA.ne.jp> Date: Wed, 22 Jun 2022 15:49:21 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Content-Language: en-US To: Russell King , Tony Lindgren Cc: LKML , Linux ARM From: Tetsuo Handa Subject: [PATCH] ARM: spectre-v2: fix smp_processor_id() warning Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" syzbot complains smp_processor_id() from harden_branch_predictor() from page fault path [1]. Explicitly disable preemption and use raw_smp_processor_id(). Link: https://syzkaller.appspot.com/bug?extid=3Da7ee43e564223f195c84 [1] Reported-by: syzbot Fixes: f5fe12b1eaee220c ("ARM: spectre-v2: harden user aborts in kernel spa= ce") Signed-off-by: Tetsuo Handa --- This patch is completely untested. arch/arm/include/asm/system_misc.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/system_misc.h b/arch/arm/include/asm/syst= em_misc.h index 98b37340376b..a92446769acd 100644 --- a/arch/arm/include/asm/system_misc.h +++ b/arch/arm/include/asm/system_misc.h @@ -20,8 +20,11 @@ typedef void (*harden_branch_predictor_fn_t)(void); DECLARE_PER_CPU(harden_branch_predictor_fn_t, harden_branch_predictor_fn); static inline void harden_branch_predictor(void) { - harden_branch_predictor_fn_t fn =3D per_cpu(harden_branch_predictor_fn, - smp_processor_id()); + harden_branch_predictor_fn_t fn; + + preempt_disable_notrace(); + fn =3D per_cpu(harden_branch_predictor_fn, raw_smp_processor_id()); + preempt_enable_no_resched_notrace(); if (fn) fn(); } --=20 2.18.4