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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,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 78FFFC282C2 for ; Fri, 8 Feb 2019 00:42:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4431D21916 for ; Fri, 8 Feb 2019 00:42:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549586547; bh=qZXdWOc89XVHySKfM2B7o0I6mdeY6kjbnFlaTHr+BGE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=K+jnyVAra3+AHLNmzuL8hZaCiLYL145ZSpPFl5JgnuWpow2b8VazCVyjhXh0TulMf /uJ8jgHBwRUwxC2g/obbD488fzRDYMxVeWEHidRROMJ/18OYl/EZyOsZ6FLem6WLP3 5UUL/ICu9iahJNyl0eNlq/yGhXsQmhfXCluJoIgg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727002AbfBHAmZ (ORCPT ); Thu, 7 Feb 2019 19:42:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:37918 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726774AbfBHAmZ (ORCPT ); Thu, 7 Feb 2019 19:42:25 -0500 Received: from devbox (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 E628921907; Fri, 8 Feb 2019 00:42:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549586544; bh=qZXdWOc89XVHySKfM2B7o0I6mdeY6kjbnFlaTHr+BGE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=f9d6Z2jktLhOUpCUmJKZmrHXdJVZjUFfU/vmP4GnJhxByXFxOdxxWgbTWtWgsG64W zGZbSuDeMkWETQ2qEdQ9yEHyvetGKRHyXu2Qz7sWH3N4nfN8AvQ2jPipWmQITUtVAp CBRCcIW/3gEuQhMMRYDc0W3Hcgy5/6/oQNsGsGpg= Date: Fri, 8 Feb 2019 09:42:20 +0900 From: Masami Hiramatsu To: Steven Rostedt Cc: Andreas Ziegler , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/3] tracing: uprobes: Re-enable $comm support for uprobe events Message-Id: <20190208094220.83ae0df5c71a9cd8891e598d@kernel.org> In-Reply-To: <20190206155243.725bc30d@gandalf.local.home> References: <154778663676.19927.12774448308165809570.stgit@devbox> <154778666570.19927.5960654930869453736.stgit@devbox> <20190206155243.725bc30d@gandalf.local.home> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-redhat-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, 6 Feb 2019 15:52:43 -0500 Steven Rostedt wrote: > On Fri, 18 Jan 2019 13:44:25 +0900 > Masami Hiramatsu wrote: > > > @@ -180,7 +183,12 @@ fetch_store_strlen(unsigned long addr) > > int len; > > void __user *vaddr = (void __force __user *) addr; > > > > - len = strnlen_user(vaddr, MAX_STRING_SIZE); > > + if (addr == (unsigned long)current->comm) { > > + len = strlen(current->comm); > > + if (len) > > + len++; > > Why only add 1 if len is non zero? Why not always do it. > > One thing, len should always be greater than 0, and the other is that > this makes it inconsistent with the NULL case of reading the address in > userspace. Agreed, it should not 0, so it should be; len = strlen(current->comm) + 1; Thank you! > > -- Steve > > > > + } else > > + len = strnlen_user(vaddr, MAX_STRING_SIZE); > > > > return (len > MAX_STRING_SIZE) ? 0 : len; -- Masami Hiramatsu