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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, 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 03058C47085 for ; Tue, 25 May 2021 14:21:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DCFAB60FF3 for ; Tue, 25 May 2021 14:21:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233930AbhEYOWj (ORCPT ); Tue, 25 May 2021 10:22:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:42712 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233918AbhEYOWh (ORCPT ); Tue, 25 May 2021 10:22:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A5FD6613F9; Tue, 25 May 2021 14:21:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621952467; bh=1NVRT3c3rAGoTvn+BDJW+JrM2M2mhYsAZiwJZ/3l5GA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=LLUjTXrgKn6t2LhNGBZpvy5ZW1SNqGaV5HPiN/ejj2muRJpl9ou/TjgNJG1RniMX8 e1YekYo5ydewHpXdDRCzuF4Wy9A4QBU23BjwmhifQptMHEwIsVAA+gvrb8OY12bsb1 Uippvv7ErxH/5sTN82T2I9q6yIZ7Fdg/DBfIbJoozHFuP1laTWDT3TJntKU5PDKw33 m8iRSaJf7rk+TEV9ohNPAvUCveD0DocK1ZcA9WBUGWrzQxRhMyuN4J4TxDTEGyrcGj Djl5n9IxPaLWIuk2HeI5CKTjkJLrSFsnXqP5yO+HauA6FFImDSQiuGG+X1Nkt01NRj 81DL9htsNEfug== Date: Tue, 25 May 2021 23:21:03 +0900 From: Masami Hiramatsu To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, rostedt@goodmis.org, naveen.n.rao@linux.vnet.ibm.com, ananth@linux.ibm.com, x86@kernel.org Subject: Re: [PATCH 2/2] x86,kprobes: WARN if kprobes tries to handle a fault Message-Id: <20210525232103.9d79ff5e396cddd2a9eb818f@kernel.org> In-Reply-To: <20210525073213.660594073@infradead.org> References: <20210525072518.791889911@infradead.org> <20210525073213.660594073@infradead.org> 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 On Tue, 25 May 2021 09:25:20 +0200 Peter Zijlstra wrote: > With the removal of kprobe::handle_fault there is no reason left that > kprobe_page_fault() would ever return true on x86, make sure it > doesn't happen by accident. OK, this is reasonable to me. Acked-by: Masami Hiramatsu Thank you! > > Signed-off-by: Peter Zijlstra (Intel) > --- > arch/x86/mm/fault.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -1186,7 +1186,7 @@ do_kern_addr_fault(struct pt_regs *regs, > return; > > /* kprobes don't want to hook the spurious faults: */ > - if (kprobe_page_fault(regs, X86_TRAP_PF)) > + if (WARN_ON_ONCE(kprobe_page_fault(regs, X86_TRAP_PF))) > return; > > /* > @@ -1239,7 +1239,7 @@ void do_user_addr_fault(struct pt_regs * > } > > /* kprobes don't want to hook the spurious faults: */ > - if (unlikely(kprobe_page_fault(regs, X86_TRAP_PF))) > + if (WARN_ON_ONCE(kprobe_page_fault(regs, X86_TRAP_PF))) > return; > > /* > > -- Masami Hiramatsu