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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY autolearn=no 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 60D7BC433E6 for ; Sun, 31 Jan 2021 20:26:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E77964E09 for ; Sun, 31 Jan 2021 20:26:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231945AbhAaUZ5 (ORCPT ); Sun, 31 Jan 2021 15:25:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232102AbhAaUWq (ORCPT ); Sun, 31 Jan 2021 15:22:46 -0500 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 301B5C061574 for ; Sun, 31 Jan 2021 12:22:04 -0800 (PST) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id AF0D61F44865 From: Gabriel Krisman Bertazi To: Linus Torvalds Cc: Yuxuan Shui , Thomas Gleixner , Andy Lutomirski , open list , "Robert O'Callahan" , Kyle Huey Subject: Re: [REGRESSION] x86/entry: TIF_SINGLESTEP handling is still broken Organization: Collabora References: <87v9bdc4yc.fsf@m5Zedd9JOGzJrf0> Date: Sun, 31 Jan 2021 15:20:16 -0500 In-Reply-To: (Linus Torvalds's message of "Sun, 31 Jan 2021 12:10:48 -0800") Message-ID: <87mtwozwn3.fsf@collabora.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds writes: > On Sun, Jan 31, 2021 at 10:54 AM Yuxuan Shui wrote: >> >> But renaming the definition in x86 is not enough, as TIF_SINGLESTEP is >> set in current_thread_info()->flags, and the same commit has removed the >> code that checks those flags. We have to also migrate TIF_SINGLESTEP from >> thread info flags to syscall work flags, to make the whole thing work again. > > Ok, so I now have the first fix merged, but what's the next step here? > > As you say, the x86 ARCH_SYSCALL_EXIT_WORK is now entirely unused. > > It's called ARCH_SYSCALL_WORK_EXIT these days, but that's for the > SYSCALL_WORK_SYSCALL_xyz flags, not for the TIF_xyz ones. > > Revert? Or does somebody have a fix patch? I think we should migrate TIF_SINGLESTEP to a SYSCALL_WORK flag as that is just a simple refactor. I can get a patch to you and Thomas during the first part of the week, for the next -rc. I will also review the x86 version of ARCH_SYSCALL_EXIT WORK to make sure i didn't miss anything else. Reverting would be slightly be annoying as it requires reverting syscall user dispatch as well. -- Gabriel Krisman Bertazi