From patchwork Mon Dec 28 12:49:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 353077 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 C76B7C433E6 for ; Mon, 28 Dec 2020 16:20:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 893772084D for ; Mon, 28 Dec 2020 16:20:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732475AbgL1NOe (ORCPT ); Mon, 28 Dec 2020 08:14:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:42382 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728680AbgL1NOb (ORCPT ); Mon, 28 Dec 2020 08:14:31 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id ADA8620728; Mon, 28 Dec 2020 13:14:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609161256; bh=6gtKOBkROwMwHTq4kWxr4EcTFxSXOrjoyeR0cg87E/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QMjIMb660e97697jYbwJVsmVKWyJgB1bqXUwhfAacka6S4dmuFie+fJ+1ZgLPKI9X GUoEQHCVHKzz0WJQE+GldOuUeQFNvMhQ4rauTek7JzeHKgbTnucDJHko33PVa+aYsa FQGZVUFO/dAS705m9AaSaiHjfwFIFE0olnaQlmU8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Masami Hiramatsu , "Peter Zijlstra (Intel)" , Sasha Levin Subject: [PATCH 4.14 155/242] x86/kprobes: Restore BTF if the single-stepping is cancelled Date: Mon, 28 Dec 2020 13:49:20 +0100 Message-Id: <20201228124912.335225697@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124904.654293249@linuxfoundation.org> References: <20201228124904.654293249@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Masami Hiramatsu [ Upstream commit 78ff2733ff352175eb7f4418a34654346e1b6cd2 ] Fix to restore BTF if single-stepping causes a page fault and it is cancelled. Usually the BTF flag was restored when the single stepping is done (in resume_execution()). However, if a page fault happens on the single stepping instruction, the fault handler is invoked and the single stepping is cancelled. Thus, the BTF flag is not restored. Fixes: 1ecc798c6764 ("x86: debugctlmsr kprobes") Signed-off-by: Masami Hiramatsu Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/160389546985.106936.12727996109376240993.stgit@devnote2 Signed-off-by: Sasha Levin --- arch/x86/kernel/kprobes/core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 02665ffef0506..700d434f5bda9 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -1022,6 +1022,11 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr) * So clear it by resetting the current kprobe: */ regs->flags &= ~X86_EFLAGS_TF; + /* + * Since the single step (trap) has been cancelled, + * we need to restore BTF here. + */ + restore_btf(); /* * If the TF flag was set before the kprobe hit,