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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no 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 12BD5C33C99 for ; Wed, 8 Jan 2020 03:02:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D969E2080A for ; Wed, 8 Jan 2020 03:02:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578452576; bh=W6HEc1BQoIiWlJA9SIyta0MUSBglN9e1a7/Yb5joxrk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=IOLl0vAE6i/J/f1T7vnfzDcUintPozpWPvrVXv4f8T9E3Es8WiOiAY5ZK7F7KVADT dMB/OYp+nGtRv+XiW1Vc3rnv6Hb1S4BsW527vKIQrOu8i34/ewsyg01he9Elfpyhb2 vCaJsDlJi/ysw0466ZxXQe/0QjRsZ77zdRUxSASI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726637AbgAHDC4 (ORCPT ); Tue, 7 Jan 2020 22:02:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:47188 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726142AbgAHDCz (ORCPT ); Tue, 7 Jan 2020 22:02:55 -0500 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (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 02A9E2075A; Wed, 8 Jan 2020 03:02:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578452575; bh=W6HEc1BQoIiWlJA9SIyta0MUSBglN9e1a7/Yb5joxrk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=n57mDStE2+vKfuvNCDQ/Aotjv8v0CZqgnznTKqM/gTrmrsj0RKlR7QhvoeE4jYtZZ GNgs1XC9V2BlTnAdEEf2UsiCin+qCgkjXKYhJ37+WVGvTZgN7rqtjwjr3j/UgjCq2S YWDQFtqTrsRVSsx+o1YRk2wA7af/Qo+IWF9Ggcx0= Date: Wed, 8 Jan 2020 12:02:49 +0900 From: Masami Hiramatsu To: Steven Rostedt 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: <20200108120249.99d5a6d5201d1401e24447bc@kernel.org> In-Reply-To: <20200107183907.3c87500a@gandalf.local.home> References: <157840814418.7181.13478003006386303481.stgit@devnote2> <20200107183907.3c87500a@gandalf.local.home> X-Mailer: Sylpheed 3.5.1 (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 18:39:07 -0500 Steven Rostedt wrote: > 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) Thank you! > > > > 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. Yeah, I felt somewhat uncomfortable for that. > > -- Steve -- Masami Hiramatsu