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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 3B3F2C433DF for ; Thu, 27 Aug 2020 12:14:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 13DE5207F7 for ; Thu, 27 Aug 2020 12:14:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598530483; bh=FJ6VppXfhXdONz0GZcmIu4gnd/OYSpzCj9s6sDvRBk8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=Ehjx01SniFs8mmgnCoDgeACjE5ZYyRun+PnualrGYR8QazGRsgyGCFndnCLnvQibg S/6E/SCBXKes7Uu6r/2G0kwowrPuwUTA4GFKZjbHPzdIIy3N9dgjXA5k0AI0XIO/Iu XnQPjo2cn2TwKCJtbfNBMEKr3KoBpRd4AlieY0BQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728987AbgH0MOi (ORCPT ); Thu, 27 Aug 2020 08:14:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:55044 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728746AbgH0Lu6 (ORCPT ); Thu, 27 Aug 2020 07:50:58 -0400 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 483462177B; Thu, 27 Aug 2020 11:50:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598529032; bh=FJ6VppXfhXdONz0GZcmIu4gnd/OYSpzCj9s6sDvRBk8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=t9vHXty5w3CKX05loqhbwow0e6e7zcsqhVW3Z5ib1F3qjHrP3er+YBf9Ahw0hln3i xBNS1q6YfTMpN3ox8Nk1QPPIYG5+uzEIXx9AvzFhHXkbExJrWm5fowdaPnZBFy893t ex/4B4P90OzkDQ0SDC3xbjIaHIeYJOLuvU5jcmzU= Date: Thu, 27 Aug 2020 20:50:28 +0900 From: Masami Hiramatsu To: peterz@infradead.org Cc: linux-kernel@vger.kernel.org, Eddy Wu , x86@kernel.org, "David S . Miller" , Steven Rostedt , Ingo Molnar , "Naveen N . Rao" , Anil S Keshavamurthy , linux-arch@vger.kernel.org Subject: Re: [PATCH v2 15/15] kprobes: Free kretprobe_instance with rcu callback Message-Id: <20200827205028.964ca2ac4cd79d4e6cee7f9f@kernel.org> In-Reply-To: <20200827114807.GA2674@hirez.programming.kicks-ass.net> References: <159852811819.707944.12798182250041968537.stgit@devnote2> <159852826969.707944.15092569392287597887.stgit@devnote2> <20200827114807.GA2674@hirez.programming.kicks-ass.net> X-Mailer: Sylpheed 3.7.0 (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 Thu, 27 Aug 2020 13:48:07 +0200 peterz@infradead.org wrote: > On Thu, Aug 27, 2020 at 08:37:49PM +0900, Masami Hiramatsu wrote: > > Free kretprobe_instance with rcu callback instead of directly > > freeing the object in the kretprobe handler context. > > > > This will make kretprobe run safer in NMI context. > > > > Signed-off-by: Masami Hiramatsu > > --- > > include/linux/kprobes.h | 3 ++- > > kernel/kprobes.c | 25 ++++++------------------- > > 2 files changed, 8 insertions(+), 20 deletions(-) > > > > diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h > > index 46a7afcf5ec0..97557f820d9b 100644 > > --- a/include/linux/kprobes.h > > +++ b/include/linux/kprobes.h > > @@ -160,6 +160,7 @@ struct kretprobe_instance { > > struct kretprobe *rp; > > kprobe_opcode_t *ret_addr; > > struct task_struct *task; > > + struct rcu_head rcu; > > void *fp; > > char data[]; > > }; > > You can stick the rcu_head in a union with hlist. Indeed. OK, I'll update it. Thank you! -- Masami Hiramatsu