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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 CAECFC4360C for ; Thu, 10 Oct 2019 21:52:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A45A5206B6 for ; Thu, 10 Oct 2019 21:52:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727403AbfJJVwT (ORCPT ); Thu, 10 Oct 2019 17:52:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:41528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725867AbfJJVwT (ORCPT ); Thu, 10 Oct 2019 17:52:19 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 40DE52067B; Thu, 10 Oct 2019 21:52:18 +0000 (UTC) Date: Thu, 10 Oct 2019 17:52:16 -0400 From: Steven Rostedt To: Masami Hiramatsu Cc: LKML , Ingo Molnar , Peter Zijlstra , "H. Peter Anvin" , Thomas Gleixner , Andrew Morton Subject: [RFC][PATCH] kprobes/x86: While list ftrace locations in kprobe blacklist areas Message-ID: <20191010175216.4ceb3cf1@gandalf.local.home> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt (VMware) I noticed some of my old tests failing on kprobes, and realized that this was due to black listing irq_entry functions on x86 from being used by kprobes. IIRC, this was due to the cr2 being corrupted and such, and I believe other things were to cause. But black listing all irq_entry code is a big hammer to this. (See commit 0eae81dc9f026 "x86/kprobes: Prohibit probing on IRQ handlers directly" for more details) Anyway, if kprobes is using ftrace as a hook, there shouldn't be any problems here. If we white list ftrace locations in the range of kprobe_add_area_blacklist(), it should be safe. Signed-off-by: Steven Rostedt (VMware) --- diff --git a/kernel/kprobes.c b/kernel/kprobes.c index d9770a5393c8..9d28a279282c 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2124,6 +2124,11 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end) int ret = 0; for (entry = start; entry < end; entry += ret) { +#ifdef CONFIG_KPROBES_ON_FTRACE + /* We are safe if using ftrace */ + if (ftrace_location(entry)) + continue; +#endif ret = kprobe_add_ksym_blacklist(entry); if (ret < 0) return ret;