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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 75E3EC7618F for ; Mon, 15 Jul 2019 11:02:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 46D00206B8 for ; Mon, 15 Jul 2019 11:02:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729909AbfGOLCY (ORCPT ); Mon, 15 Jul 2019 07:02:24 -0400 Received: from 8bytes.org ([81.169.241.247]:35386 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729844AbfGOLCY (ORCPT ); Mon, 15 Jul 2019 07:02:24 -0400 Received: by theia.8bytes.org (Postfix, from userid 1000) id 948EB41D; Mon, 15 Jul 2019 13:02:22 +0200 (CEST) From: Joerg Roedel To: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Joerg Roedel Subject: [PATCH 3/3] mm/vmalloc: Sync unmappings in vunmap_page_range() Date: Mon, 15 Jul 2019 13:02:12 +0200 Message-Id: <20190715110212.18617-4-joro@8bytes.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190715110212.18617-1-joro@8bytes.org> References: <20190715110212.18617-1-joro@8bytes.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joerg Roedel On x86-32 with PTI enabled, parts of the kernel page-tables are not shared between processes. This can cause mappings in the vmalloc/ioremap area to persist in some page-tables after the regions is unmapped and released. When the region is re-used the processes with the old mappings do not fault in the new mappings but still access the old ones. This causes undefined behavior, in reality often data corruption, kernel oopses and panics and even spontaneous reboots. Fix this problem by activly syncing unmaps in the vmalloc/ioremap area to all page-tables in the system. References: https://bugzilla.suse.com/show_bug.cgi?id=1118689 Fixes: 7757d607c6b3 ('x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32') Signed-off-by: Joerg Roedel --- mm/vmalloc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 4fa8d84599b0..322b11a374fd 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -132,6 +132,8 @@ static void vunmap_page_range(unsigned long addr, unsigned long end) continue; vunmap_p4d_range(pgd, addr, next); } while (pgd++, addr = next, addr != end); + + vmalloc_sync_all(); } static int vmap_pte_range(pmd_t *pmd, unsigned long addr, -- 2.17.1