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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A835AC433EF for ; Thu, 7 Jul 2022 18:04:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236067AbiGGSEN (ORCPT ); Thu, 7 Jul 2022 14:04:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36630 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236048AbiGGSEK (ORCPT ); Thu, 7 Jul 2022 14:04:10 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A59CF13F42; Thu, 7 Jul 2022 11:04:09 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 67487B82299; Thu, 7 Jul 2022 18:04:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB409C3411E; Thu, 7 Jul 2022 18:04:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657217047; bh=SGueRWIyzVyPJjQ6UwiSli1wQJuF/A3j5F+SxexRI4M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=2A5xUmgMvNbXPxl0c/R7AwoUOgkkfPPoho0gVa7Al9D4+G4UxVZ5/2GaxeK2Nu180 KsO0n28XxX7SeLQoxzWNZZUdolFCkDjEusGD0JasBw9Bh2c7UMe//TBl2oVGuIP/iy qPRtKS17zKmhXLOdy7QwHCSF1pSAyPDZUbffqPKY= Date: Thu, 7 Jul 2022 20:04:04 +0200 From: Greg Kroah-Hartman To: Matthew Wilcox Cc: Liu Shixin , Andrew Morton , Jan Kara , William Kucharski , Christoph Hellwig , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 5.15 v4] mm/filemap: fix UAF in find_lock_entries Message-ID: References: <20220707020938.2122198-1-liushixin2@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 07, 2022 at 04:09:29AM +0100, Matthew Wilcox wrote: > On Thu, Jul 07, 2022 at 10:09:38AM +0800, Liu Shixin wrote: > > Release refcount after xas_set to fix UAF which may cause panic like this: > > > > page:ffffea000491fa40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1247e9 > > head:ffffea000491fa00 order:3 compound_mapcount:0 compound_pincount:0 > > memcg:ffff888104f91091 > > flags: 0x2fffff80010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff) > > ... > > page dumped because: VM_BUG_ON_PAGE(PageTail(page)) > > ------------[ cut here ]------------ > > kernel BUG at include/linux/page-flags.h:632! > > invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN > > CPU: 1 PID: 7642 Comm: sh Not tainted 5.15.51-dirty #26 > > ... > > Call Trace: > > > > __invalidate_mapping_pages+0xe7/0x540 > > drop_pagecache_sb+0x159/0x320 > > iterate_supers+0x120/0x240 > > drop_caches_sysctl_handler+0xaa/0xe0 > > proc_sys_call_handler+0x2b4/0x480 > > new_sync_write+0x3d6/0x5c0 > > vfs_write+0x446/0x7a0 > > ksys_write+0x105/0x210 > > do_syscall_64+0x35/0x80 > > entry_SYSCALL_64_after_hwframe+0x44/0xae > > RIP: 0033:0x7f52b5733130 > > ... > > > > This problem has been fixed on mainline by patch 6b24ca4a1a8d ("mm: Use > > multi-index entries in the page cache") since it deletes the related code. > > > > Fixes: 5c211ba29deb ("mm: add and use find_lock_entries") > > Signed-off-by: Liu Shixin > > Acked-by: Matthew Wilcox (Oracle) Now queued up, thanks. greg k-h