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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 45FE3ECDFAA for ; Mon, 16 Jul 2018 12:41:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E330F2084E for ; Mon, 16 Jul 2018 12:41:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E330F2084E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730922AbeGPNI5 (ORCPT ); Mon, 16 Jul 2018 09:08:57 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:51854 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728524AbeGPNI5 (ORCPT ); Mon, 16 Jul 2018 09:08:57 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 42B4877885; Mon, 16 Jul 2018 12:41:40 +0000 (UTC) Received: from treble (ovpn-122-49.rdu2.redhat.com [10.10.122.49]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F0F6F7C4D; Mon, 16 Jul 2018 12:41:39 +0000 (UTC) Date: Mon, 16 Jul 2018 07:41:38 -0500 From: Josh Poimboeuf To: Kamalesh Babulal Cc: Miroslav Benes , Jiri Kosina , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] livepatch: Remove reliable stacktrace check in klp_try_switch_task() Message-ID: <20180716124138.pyqbiviqoxcbs44g@treble> References: <1531382706-9732-1-git-send-email-kamalesh@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1531382706-9732-1-git-send-email-kamalesh@linux.vnet.ibm.com> User-Agent: NeoMutt/20180323 X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Mon, 16 Jul 2018 12:41:40 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Mon, 16 Jul 2018 12:41:40 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jpoimboe@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 12, 2018 at 01:35:06PM +0530, Kamalesh Babulal wrote: > Support for immediate flag was removed by commit d0807da78e11 > ("livepatch: Remove immediate feature"). We bail out during > patch registration for architectures, those don't support > reliable stack trace. Remove the check in klp_try_switch_task(), > as its not required. > > Signed-off-by: Kamalesh Babulal Acked-by: Josh Poimboeuf > --- > kernel/livepatch/transition.c | 7 ------- > 1 file changed, 7 deletions(-) > > diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c > index 7c6631e693bc..5bc349805e03 100644 > --- a/kernel/livepatch/transition.c > +++ b/kernel/livepatch/transition.c > @@ -310,13 +310,6 @@ static bool klp_try_switch_task(struct task_struct *task) > return true; > > /* > - * For arches which don't have reliable stack traces, we have to rely > - * on other methods (e.g., switching tasks at kernel exit). > - */ > - if (!klp_have_reliable_stack()) > - return false; > - > - /* > * Now try to check the stack for any to-be-patched or to-be-unpatched > * functions. If all goes well, switch the task to the target patch > * state. > -- > 2.7.4 > -- Josh