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=-11.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 68A0FC433ED for ; Thu, 1 Apr 2021 00:32:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 180D360FEC for ; Thu, 1 Apr 2021 00:32:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232540AbhDAAbK (ORCPT ); Wed, 31 Mar 2021 20:31:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:44986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229486AbhDAAak (ORCPT ); Wed, 31 Mar 2021 20:30:40 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C2C546101E; Thu, 1 Apr 2021 00:30:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617237040; bh=62oBHtP8b4XwyEoNVJI6VmhrBZdgCYFCTbD8I+sP/zg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=kW/E6LbgqWEEZAvhHiViofcw5zhxPQblmj3TNdcAS3uwY90IWH7VBOq8nCZPcsyBI WfGxVMo/O0WED0VA8ycLnreGZ5zQFUQEQ+otYNAxAIYhkwGMopGSPl8/VW7VPsNABl 4iNicD4J2OkAAgUt5uET2fEDmtMlrvufR2/KJw81J6uIytfaR/hpg9x9pMvroVq3S9 RRC+UbZ/Kr8dpzqeKOwVgb9Xvp1kg70kXuIwMHezmrrsq42DxMrIuduQJwFfzLXTZz 9nfteii8VYEc6Bp1fpZZ4IE8V+zoZ4y1FLVA3DBXBE33AfdBOXX87VDtRRyeb+cag9 VHqKnyOnshqhA== Date: Thu, 1 Apr 2021 09:30:36 +0900 From: Masami Hiramatsu To: Jisheng Zhang Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , Guo Ren , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] riscv: keep interrupts disabled for BREAKPOINT exception Message-Id: <20210401093036.037f2abbce7ed5d1e68466b7@kernel.org> In-Reply-To: <20210331222244.45a5807c@xhacker> References: <20210330021624.2b776386@xhacker> <20210330183316.942215efe8e6e8455ad14113@kernel.org> <20210331222244.45a5807c@xhacker> 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Wed, 31 Mar 2021 22:22:44 +0800 Jisheng Zhang wrote: > On Tue, 30 Mar 2021 18:33:16 +0900 > Masami Hiramatsu wrote: > > > Hi Jisheng, > > Hi Masami, > > > > > On Tue, 30 Mar 2021 02:16:24 +0800 > > Jisheng Zhang wrote: > > > > > From: Jisheng Zhang > > > > > > Current riscv's kprobe handlers are run with both preemption and > > > interrupt enabled, this violates kprobe requirements. Fix this issue > > > by keeping interrupts disabled for BREAKPOINT exception. > > > > Not only while the breakpoint exception but also until the end of > > the single step (maybe you are using __BUG_INSN_32 ??) need to be > > disable interrupts. Can this do that? > > > > interrupt is disabled during "single step" by kprobes_save_local_irqflag() > and kprobes_restore_local_irqflag(). The code flow looks like: > > do_trap_break() // for bp > kprobe_breakpoint_handler() > setup_singlestep() > kprobes_restore_local_irqflag() > > do_trap_break() // for ss > kprobe_single_step_handler() > kprobes_restore_local_irqflag() OK, thanks for the confirmation! Reviewed-by: Masami Hiramatsu Thanks, -- Masami Hiramatsu