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[209.132.180.67]) by mx.google.com with ESMTP id 1si249318plq.153.2019.08.14.10.10.19; Wed, 14 Aug 2019 10:10:35 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=ZRyMb+Qh; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729412AbfHNRI5 (ORCPT + 99 others); Wed, 14 Aug 2019 13:08:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:59118 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730216AbfHNRIy (ORCPT ); Wed, 14 Aug 2019 13:08:54 -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 618E721721; Wed, 14 Aug 2019 17:08:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565802533; bh=fllYO8klzVBu/v/RKi/Wr7MUFDeaUMeXiVuI1JnUge0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZRyMb+QhZ5l1qOOUu7dDHKs5kMKbGikggXm0DItWTI0BtogkEVHvF6E87/PSSZ8IG lUeY25iDTDQ6sFZ39umXU4Ilz4nYCxh0/0Uug5/9KXSKSxqnuhawsghCvKx5mq8LbM ttrj/MUvv76/I6rd0ybEF+AGqHpD3KftYX1wa2HY= 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 4.19 19/91] mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy() Date: Wed, 14 Aug 2019 19:00:42 +0200 Message-Id: <20190814165750.551462071@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190814165748.991235624@linuxfoundation.org> References: <20190814165748.991235624@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 @@ -1752,6 +1752,12 @@ void *__vmalloc_node_range(unsigned long return NULL; /* + * First make sure the mappings are removed from all page-tables + * before they are freed. + */ + vmalloc_sync_all(); + + /* * In this function, newly allocated vm_struct has VM_UNINITIALIZED * flag. It means that vm_struct is not fully initialized. * Now, it is fully initialized, so remove this flag here. @@ -2296,6 +2302,9 @@ 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) {