From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966623AbcIZUBo (ORCPT ); Mon, 26 Sep 2016 16:01:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58020 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965363AbcIZUBj (ORCPT ); Mon, 26 Sep 2016 16:01:39 -0400 Date: Mon, 26 Sep 2016 15:01:36 -0500 From: Josh Poimboeuf To: Mark Rutland Cc: linux-kernel@vger.kernel.org, Andrew Morton , Eric Dumazet , Greg Kroah-Hartman , Ingo Molnar , Jiri Slaby , Peter Zijlstra Subject: Re: [PATCH 0/3] Kill off show_stack() NULL-implies-current idiom Message-ID: <20160926200136.sbltg4tp5uft4yfo@treble> References: <1474902979-18436-1-git-send-email-mark.rutland@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1474902979-18436-1-git-send-email-mark.rutland@arm.com> User-Agent: Mutt/1.6.0.1 (2016-04-01) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Mon, 26 Sep 2016 20:01:38 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 26, 2016 at 04:16:16PM +0100, Mark Rutland wrote: > Today, show_stack() accepts a NULL task parameter, which it takes to mean the > current task. However, as noted in tip/x86/asm commit: > > 81539169f283329f ("x86/dumpstack: Remove NULL task pointer convention") > > ... having a NULL task parameter imply current leads to subtle bugs in stack > walking code (so far seen on both 86 and arm64), makes callsites harder to > read, and is unnecessary as all callers have access to current. > > As a step towards removing the problematic NULL-implies-current idiom entirely, > these patches ensure that generic code explictly passes current to > show_stack(), rather than relying on arch code to handle NULL. This is a good step, though it would be really nice to fix this tree-wide. Do you have any plans to do so? Regardless, for the series: Reviewed-by: Josh Poimboeuf -- Josh