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=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,NICE_REPLY_A, 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 E09E0C433E1 for ; Wed, 26 Aug 2020 08:22:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A768C207DF for ; Wed, 26 Aug 2020 08:22:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598430166; bh=tMISGZM36b6tDxevjrHPUUnvWJiWBP+nHFBD81rP+qY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=S+7Vg2aOTv51vqka01EDKiuf521TPxJTr0kIxYFTEItnM2+vfIZzLgjgWu1nvi8jC vHHdn7EqGkPiCwS9LBlk237Cok4yGwDrL6PjSh/UYtqrAIWWaATYACLNE7czH4LDOE puu7+NIEV1nKYYv/mEtfQaHbcTRV+QG7IHdKvnWU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726856AbgHZIWp (ORCPT ); Wed, 26 Aug 2020 04:22:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:41658 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726016AbgHZIWn (ORCPT ); Wed, 26 Aug 2020 04:22:43 -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 AA3D0206FA; Wed, 26 Aug 2020 08:22:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598430163; bh=tMISGZM36b6tDxevjrHPUUnvWJiWBP+nHFBD81rP+qY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=G79Fe12Y89Eu3aNxs4J3/GULNRuXsKglnE8fSDjN3IrjhnQUuJjR4JJho0h3s9WOt mAhRz6Mi/YAjsu6LT3pUiKGdV2oQpe8bZYYMBIx7BfBGebMK9D/qjhzxLzFMag3PhZ +0co3rdCfUrk/BmOTOAg5NCQXjxnAIxrSVGZN7zc= Date: Wed, 26 Aug 2020 17:22:39 +0900 From: Masami Hiramatsu To: "Eddy_Wu@trendmicro.com" Cc: "peterz@infradead.org" , Masami Hiramatsu , "linux-kernel@vger.kernel.org" , "x86@kernel.org" Subject: Re: x86/kprobes: kretprobe fails to triggered if kprobe at function entry is not optimized (trigger by int3 breakpoint) Message-Id: <20200826172239.ff175be78ee5f3a4380579c3@kernel.org> In-Reply-To: References: <8816bdbbc55c4d2397e0b02aad2825d3@trendmicro.com> <20200825005426.f592075d13be740cb3c9aa77@kernel.org> <7396e7b2079644a6aafd9670a111232b@trendmicro.com> <20200825151538.f856d701a34f4e0561a64932@kernel.org> <20200825120911.GX1362448@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 Wed, 26 Aug 2020 07:07:09 +0000 "Eddy_Wu@trendmicro.com" wrote: > > > -----Original Message----- > > From: peterz@infradead.org > > Sent: Tuesday, August 25, 2020 8:09 PM > > To: Masami Hiramatsu > > Cc: Eddy Wu (RD-TW) ; linux-kernel@vger.kernel.org; x86@kernel.org; David S. Miller > > > > Subject: Re: x86/kprobes: kretprobe fails to triggered if kprobe at function entry is not optimized (trigger by int3 breakpoint) > > > > Surely we can do a lockless list for this. We have llist_add() and > > llist_del_first() to make a lockless LIFO/stack. > > > > llist operations require atomic cmpxchg, for some arch doesn't have CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, in_nmi() check might still needed. > (HAVE_KRETPROBES && !CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG): arc, arm, csky, mips Good catch. In those cases, we can add in_nmi() check at arch dependent code. Thank you, -- Masami Hiramatsu