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=-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 9A40DC4332E for ; Mon, 28 Dec 2020 16:32:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 614C5229C5 for ; Mon, 28 Dec 2020 16:32:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2441907AbgL1QcR (ORCPT ); Mon, 28 Dec 2020 11:32:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:60432 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730398AbgL1NER (ORCPT ); Mon, 28 Dec 2020 08:04:17 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id CE0DD22583; Mon, 28 Dec 2020 13:03:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609160616; bh=S6MYLTteBd2F4CN61YD9SP2wyUzE9VfO13Em9rb6hzk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zy59Dwo03RqfDVJr3ELFLIjS5CGYRQh9VmXskiTBLKfTt86MjGoc8DBE2GHEKjq1M geof+XM8rZHbEViVqg6EdiEPU6NkScTscVUdr8ycwcl9IhovbcB6lQgAAYVtDFMkEv JNaWhc5t7V/lTX27MDxfMVZXnHbY4nP8jAfyOiCo= 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 4.9 111/175] x86/kprobes: Restore BTF if the single-stepping is cancelled Date: Mon, 28 Dec 2020 13:49:24 +0100 Message-Id: <20201228124858.632467448@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124853.216621466@linuxfoundation.org> References: <20201228124853.216621466@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 86aec286e4f22..3da08881a0104 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -1018,6 +1018,11 @@ 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, -- 2.27.0