From patchwork Sun Apr 23 01:27:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Zhongjin X-Patchwork-Id: 86649 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp1974804vqo; Sat, 22 Apr 2023 18:42:47 -0700 (PDT) X-Google-Smtp-Source: AKy350Yztt2WbY+KPHstO+69P+wSb17uuj38l136yeepyQVXhQV+SKb/0iHZtqidrkOnD5lzvUsW X-Received: by 2002:a05:6a20:7350:b0:f2:745a:b87e with SMTP id v16-20020a056a20735000b000f2745ab87emr9428989pzc.12.1682214166976; Sat, 22 Apr 2023 18:42:46 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1682214166; cv=none; d=google.com; s=arc-20160816; b=rvvAwuIHpoZQrwzs8+YlbxBWsWZL9Z1BmyYw1lWU5W0n0uYOTxWCcktUq+ZyhZUuAs 2wf3Eeweh4AbB2NLmfHNdFEUadv5i7uJLHDABRPC43HR1hKg3hpAvqsKnv29uMI+TeM+ QZcRW57rL/QwxmDx4DwAR/RP2y17o3vDvtCPvHlwqWG6/ZODVeEaHCT++F4rM/jCXtt2 4TXj5khWz4NnyVFfDF79AFRf58fkGNUVkgp/aMZgYanldHGhYKz5mGfhJCa3agGqAtm1 PeQ0QSeuiyO+WdsfaDpTF3CPcDLucnX1jAwCHVxHediTcsqaskUoPn5RnWcZGdoxLTNQ eVJw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:message-id:date:subject:cc:to:from; bh=kfi5MVSvsvLSXZjxDHOyba8lbRw1SEEzMlrx4zaUKjk=; b=mzjx7HHEoPHsADkpBLFjCQOJ4m/KwBgNAMMtRimj8+eBVGQq/YxmMSwlEvZGNxdR5q DjuV+ALpWapkw+GIhtYespyzJJkJgA0XxYxYEowNenCR42zo5Litnas6pXOce5c1h21j PLPKcSk0eZ8LYkEVO6WMyzCbyLoOFgAwLjMWE5bAe4wQuH4BpqvXP0nWsF55Zfci3v5p R99e1IZSQaQg2Zqa3aNGmv+eii/q8S4mYJ5SKL+s2+XtIpDhh8fSCgWyUV5JeDiBF77c wnnDLms0dPmYYVy3Kgo3m100gduCePyP28ImGTYmgQc4mB3qZvdql7kNU4tUvIOzsnNi 7hpA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id z21-20020a63e115000000b0051eff07b9f5si7732081pgh.84.2023.04.22.18.42.34; Sat, 22 Apr 2023 18:42:46 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229963AbjDWB3o (ORCPT + 99 others); Sat, 22 Apr 2023 21:29:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229556AbjDWB3n (ORCPT ); Sat, 22 Apr 2023 21:29:43 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99FA52735 for ; Sat, 22 Apr 2023 18:29:17 -0700 (PDT) Received: from dggpemm500013.china.huawei.com (unknown [172.30.72.55]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4Q3rHm0DnXzKtZm; Sun, 23 Apr 2023 09:28:20 +0800 (CST) Received: from ubuntu1804.huawei.com (10.67.175.36) by dggpemm500013.china.huawei.com (7.185.36.172) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Sun, 23 Apr 2023 09:29:15 +0800 From: Chen Zhongjin To: CC: , , , , , , , , , Subject: [PATCH v3] x86: profiling: remove lock functions profiling in profile_pc Date: Sun, 23 Apr 2023 09:27:44 +0800 Message-ID: <20230423012744.24320-1-chenzhongjin@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.67.175.36] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm500013.china.huawei.com (7.185.36.172) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1763929402078600995?= X-GMAIL-MSGID: =?utf-8?q?1763929402078600995?= Syzbot has been reporting the problem of stack-out-of-bounds in profile_pc for a long time: https://syzkaller.appspot.com/bug?extid=84fe685c02cd112a2ac3 profile_pc will get return address for caller if current function is lock function. For !CONFIG_FRAME_POINTER it uses a hack way to get the caller by directly reading sp[0] or sp [1]. It not works when KASAN is enabled because KASAN pushes data on stack which makes sp[0/1] become KASAN red zone. Then profile_pc reads wrong memory and triggers KASAN warning frequently. This hack might be ok when first added at 2006 but now it's different: 1. There are some lock functions which have frame longer than two stack slots. For these functions sp[0/1] is not a legal return address even KASAN is not enabled. 2. !CONFIG_FRAME_POINTER is more used today because UNWINDER_ORC. 3. Lock function caller information can be prfiled by perf better. Since profile as a low level facility it's not proper to depend on complex generic unwinder to get the next frame. As lock profiling is no longer useful, it's fine to remove it. Fixes: 0cb91a229364 ("[PATCH] i386: Account spinlocks to the caller during profiling for !FP kernels") Suggested-by: Andi Kleen Signed-off-by: Chen Zhongjin --- v1->v2: Make a more detailed commit log. v2->v3: Also remove if for FRAME_POINTER case; slightly fix the commit log. --- arch/x86/kernel/time.c | 20 +------------------- 1 file changed, 1 insertion(+), 19 deletions(-) diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c index e42faa792c07..52e1f3f0b361 100644 --- a/arch/x86/kernel/time.c +++ b/arch/x86/kernel/time.c @@ -27,25 +27,7 @@ unsigned long profile_pc(struct pt_regs *regs) { - unsigned long pc = instruction_pointer(regs); - - if (!user_mode(regs) && in_lock_functions(pc)) { -#ifdef CONFIG_FRAME_POINTER - return *(unsigned long *)(regs->bp + sizeof(long)); -#else - unsigned long *sp = (unsigned long *)regs->sp; - /* - * Return address is either directly at stack pointer - * or above a saved flags. Eflags has bits 22-31 zero, - * kernel addresses don't. - */ - if (sp[0] >> 22) - return sp[0]; - if (sp[1] >> 22) - return sp[1]; -#endif - } - return pc; + return instruction_pointer(regs); } EXPORT_SYMBOL(profile_pc);