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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 C63F5C76196 for ; Fri, 19 Jul 2019 06:01:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A9D7C2085A for ; Fri, 19 Jul 2019 06:01:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727109AbfGSGBC (ORCPT ); Fri, 19 Jul 2019 02:01:02 -0400 Received: from verein.lst.de ([213.95.11.211]:37200 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726072AbfGSGBC (ORCPT ); Fri, 19 Jul 2019 02:01:02 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 2F96268BFE; Fri, 19 Jul 2019 08:00:55 +0200 (CEST) Date: Fri, 19 Jul 2019 08:00:53 +0200 From: Christoph Hellwig To: David Miller Cc: ldv@altlinux.org, hch@lst.de, khalid.aziz@oracle.com, torvalds@linux-foundation.org, akpm@linux-foundation.org, matorola@gmail.com, sparclinux@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 09/16] sparc64: use the generic get_user_pages_fast code Message-ID: <20190719060053.GA18491@lst.de> References: <20190625143715.1689-1-hch@lst.de> <20190625143715.1689-10-hch@lst.de> <20190717215956.GA30369@altlinux.org> <20190718.141405.1070121094691581998.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190718.141405.1070121094691581998.davem@davemloft.net> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 18, 2019 at 02:14:05PM -0700, David Miller wrote: > From: "Dmitry V. Levin" > Date: Thu, 18 Jul 2019 00:59:56 +0300 > > > So this ended up as commit 7b9afb86b6328f10dc2cad9223d7def12d60e505 > > (thanks to Anatoly for bisecting) and introduced a regression: > > futex.test from the strace test suite now causes an Oops on sparc64 > > in futex syscall. > > > > Here is a heavily stripped down reproducer: > > Does not reproduce for me on a T4-2 machine. > > So this problem might depend on the type of system you are on, > I suspect it's one of those "pre-Niagara vs. Niagara and later" > situations because that's the dividing line between two set of > wildly different TLB and cache management methods. > > What kind of machine are you on? FYI, I'm pretty sure I tested this on Guenthers build test qemu setup in the end, which further speaks for the different machines issue.