Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751938AbdI2GsW (ORCPT ); Fri, 29 Sep 2017 02:48:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:34598 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750709AbdI2GsU (ORCPT ); Fri, 29 Sep 2017 02:48:20 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 13BAB218BC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=mhiramat@kernel.org Date: Thu, 28 Sep 2017 23:48:18 -0700 From: Masami Hiramatsu To: Ingo Molnar Cc: mingo@redhat.com, x86@kernel.org, Steven Rostedt , linux-kernel@vger.kernel.org, Peter Zijlstra , Ananth N Mavinakayanahalli , Thomas Gleixner , "H . Peter Anvin" , "Paul E . McKenney" , Alexei Starovoitov , Alexei Starovoitov Subject: Re: [PATCH -tip v3 6/7] kprobes/x86: Remove disable_irq from ftrace-based/optimized kprobe Message-Id: <20170928234818.e5fa6732dee4bd17b489b91f@kernel.org> In-Reply-To: <20170928072541.daf7oqj6tkq4vmac@gmail.com> References: <150581509713.32348.1905525476438163954.stgit@devbox> <150581534039.32348.11331736206004264553.stgit@devbox> <20170928072541.daf7oqj6tkq4vmac@gmail.com> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.30; 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1287 Lines: 48 On Thu, 28 Sep 2017 09:25:41 +0200 Ingo Molnar wrote: > > * Masami Hiramatsu wrote: > > > Actually kprobes doesn't need to disable irq if it is > > called from ftrace/jump trampoline code because > > Documentation/kprobes.txt says > > > > ----- > > Probe handlers are run with preemption disabled. Depending on the > > architecture and optimization state, handlers may also run with > > interrupts disabled (e.g., kretprobe handlers and optimized kprobe > > handlers run without interrupt disabled on x86/x86-64). > > ----- > > > > So let's remove irq disabling from those handlers. > > > - local_irq_save(flags); > > The title is talking about disable_irq(): > > kprobes/x86: Remove disable_irq from ftrace-based/optimized kprobe > > ... but the patch is actually using local_irq_save(), which is an entirely > different thing! You probably wanted to say: > > kprobes/x86: Remove irq disabling from ftrace-based/optimized kprobes Correct! That's my mistake. thanks! > > Also note the plural of 'kprobes' when we refer to them as a generic thing. > > I fixed the title, but _please_ read changelogs more carefully before sending > them. Thank you again, > > Thanks, > > Ingo -- Masami Hiramatsu