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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 778A9C32753 for ; Wed, 14 Aug 2019 17:03:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4EFDE2084D for ; Wed, 14 Aug 2019 17:03:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565802239; bh=SJmBCSPDxyO5xYp/rxqIK+nCIOJDRvTnyp5P/YzQDqA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jbpgXmyW8xRQyWdoknH5OKixWWvh1fJ95cn7ynnzyKbNv9L7KTEOAy024QzIuojyc VZ6vU89zHxQq1sCjbGfyTKSxofsJgTZ4cp9c42StR+gpjnAL3ykiIlqsn0QsvAeGDI S4PBu+wm/KiU8DDEQWzxamRQ2v8fF7D73R3E1b7Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729087AbfHNRD6 (ORCPT ); Wed, 14 Aug 2019 13:03:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:52684 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728527AbfHNRD4 (ORCPT ); Wed, 14 Aug 2019 13:03:56 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 14F4D208C2; Wed, 14 Aug 2019 17:03:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565802235; bh=SJmBCSPDxyO5xYp/rxqIK+nCIOJDRvTnyp5P/YzQDqA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UmnbXZo7sFws8OkfpNLcfqhqMswPRRh4KGauEYf0vPUmqc7VOh1l8b5Pi5bfmti5I Tqyn9HkSIdzmTH8Oi1ek00a5u3h8G1GWzZg2bo4v3VlRUSYFssHsXf52ZXM0WHoCdW Qg8xC1PTk6iZ7FuIf1TcYsGjJJU7VzpuWDNeT1MA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Joerg Roedel , Thomas Gleixner , Dave Hansen Subject: [PATCH 5.2 029/144] mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy() Date: Wed, 14 Aug 2019 18:59:45 +0200 Message-Id: <20190814165801.057660943@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190814165759.466811854@linuxfoundation.org> References: <20190814165759.466811854@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joerg Roedel commit 3f8fd02b1bf1d7ba964485a56f2f4b53ae88c167 upstream. 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 region 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 before the regions can be re-used. Fixes: 5d72b4fba40ef ('x86, mm: support huge I/O mapping capability I/F') Signed-off-by: Joerg Roedel Signed-off-by: Thomas Gleixner Reviewed-by: Dave Hansen Link: https://lkml.kernel.org/r/20190719184652.11391-4-joro@8bytes.org Signed-off-by: Greg Kroah-Hartman --- mm/vmalloc.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1214,6 +1214,12 @@ static bool __purge_vmap_area_lazy(unsig return false; /* + * First make sure the mappings are removed from all page-tables + * before they are freed. + */ + vmalloc_sync_all(); + + /* * TODO: to calculate a flush range without looping. * The list can be up to lazy_max_pages() elements. */ @@ -3001,6 +3007,9 @@ EXPORT_SYMBOL(remap_vmalloc_range); /* * Implement a stub for vmalloc_sync_all() if the architecture chose not to * have one. + * + * The purpose of this function is to make sure the vmalloc area + * mappings are identical in all page-tables in the system. */ void __weak vmalloc_sync_all(void) {