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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 A778FC282DD for ; Tue, 7 Jan 2020 23:39:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 70771207E0 for ; Tue, 7 Jan 2020 23:39:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727594AbgAGXjL (ORCPT ); Tue, 7 Jan 2020 18:39:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:58906 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726530AbgAGXjL (ORCPT ); Tue, 7 Jan 2020 18:39:11 -0500 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 8E69B2072A; Tue, 7 Jan 2020 23:39:09 +0000 (UTC) Date: Tue, 7 Jan 2020 18:39:07 -0500 From: Steven Rostedt To: Masami Hiramatsu Cc: Ingo Molnar , Alexei Starovoitov , Andy Lutomirski , Borislav Petkov , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , bristot@redhat.com, "Naveen N . Rao" , Anil S Keshavamurthy , David Miller , Linux Kernel Mailing List Subject: Re: [BUGFIX PATCH] kprobes: Fix to cancel optimizing/unoptimizing kprobes correctly Message-ID: <20200107183907.3c87500a@gandalf.local.home> In-Reply-To: <157840814418.7181.13478003006386303481.stgit@devnote2> References: <157840814418.7181.13478003006386303481.stgit@devnote2> 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 On Tue, 7 Jan 2020 23:42:24 +0900 Masami Hiramatsu wrote: > optimize_kprobe() and unoptimize_kprobe() cancels if given kprobe > is on the optimizing_list or unoptimizing_list. However, since > commit f66c0447cca1 ("kprobes: Set unoptimized flag after > unoptimizing code") modified the update timing of the > KPROBE_FLAG_OPTIMIZED, it doesn't work as expected anymore. > > The optimized_kprobe could be following states. > > - [optimizing]: Before inserting jump instruction > op.kp->flags has KPROBE_FLAG_OPTIMIZED and > op->list is not empty. > > - [optimized]: jump inserted > op.kp->flags has KPROBE_FLAG_OPTIMIZED and > op->list is empty. > > - [unoptimizing]: Before removing jump instruction (including unused > optprobe) > op.kp->flags has KPROBE_FLAG_OPTIMIZED and > op->list is not empty. > > - [unoptimized]: jump removed > op.kp->flags doesn't have KPROBE_FLAG_OPTIMIZED and > op->list is empty. > > Current code mis-expects [unoptimizing] state doesn't have > KPROBE_FLAG_OPTIMIZED, and that can cause wrong results. > > This introduces optprobe_queued_unopt() to distinguish [optimizing] > and [unoptimizing] states and fixes logics in optimize_kprobe() and > unoptimize_kprobe(). > > Fixes: f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code") > Signed-off-by: Masami Hiramatsu Looks good. Reviewed-by: Steven Rostedt (VMware) > return; > } > + > /* Optimized kprobe case */ > - if (force) > + if (force) { > /* Forcibly update the code: this is a special case */ > force_unoptimize_kprobe(op); > - else { > + } else { > list_add(&op->list, &unoptimizing_list); > kick_kprobe_optimizer(); > } I see you added some clean up to this patch. -- Steve