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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=unavailable 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 6D232C47257 for ; Fri, 8 May 2020 18:58:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FF5F21974 for ; Fri, 8 May 2020 18:58:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727107AbgEHS61 (ORCPT ); Fri, 8 May 2020 14:58:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:38382 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726767AbgEHS61 (ORCPT ); Fri, 8 May 2020 14:58:27 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 8924D2083B; Fri, 8 May 2020 18:58:25 +0000 (UTC) Date: Fri, 8 May 2020 14:58:22 -0400 From: Steven Rostedt To: Joerg Roedel Cc: x86@kernel.org, hpa@zytor.com, Dave Hansen , Andy Lutomirski , Peter Zijlstra , rjw@rjwysocki.net, Arnd Bergmann , Andrew Morton , Vlastimil Babka , Michal Hocko , Joerg Roedel , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH 6/7] mm: Remove vmalloc_sync_(un)mappings() Message-ID: <20200508145822.07fcc32b@gandalf.local.home> In-Reply-To: <20200508144043.13893-7-joro@8bytes.org> References: <20200508144043.13893-1-joro@8bytes.org> <20200508144043.13893-7-joro@8bytes.org> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-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 Fri, 8 May 2020 16:40:42 +0200 Joerg Roedel wrote: > From: Joerg Roedel > > These functions are not needed anymore because the vmalloc and ioremap > mappings are now synchronized when they are created or teared down. > > Remove all callers and function definitions. > > Signed-off-by: Joerg Roedel > You'll need to fold this into this patch, as my patch has already hit Linus's tree. But I applied your whole series and I'm not able to reproduce the bug. Tested-by: Steven Rostedt (VMware) -- Steve diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 29615f15a820..1424a89193c6 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8526,19 +8526,6 @@ static int allocate_trace_buffers(struct trace_array *tr, int size) */ allocate_snapshot = false; #endif - - /* - * Because of some magic with the way alloc_percpu() works on - * x86_64, we need to synchronize the pgd of all the tables, - * otherwise the trace events that happen in x86_64 page fault - * handlers can't cope with accessing the chance that a - * alloc_percpu()'d memory might be touched in the page fault trace - * event. Oh, and we need to audit all other alloc_percpu() and vmalloc() - * calls in tracing, because something might get triggered within a - * page fault trace event! - */ - vmalloc_sync_mappings(); - return 0; }