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=-8.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS 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 EBE27C433DF for ; Fri, 21 Aug 2020 20:03:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B172F2076E for ; Fri, 21 Aug 2020 20:03:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598040220; bh=yqh1mdXpcSLnQ7YmrqYC/jS5nW+Rhe7nFWcK9Uz415c=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=apwg9ShEAZknuY4Fnke7ypPTMUH8cHqAz3eD6YnSZvYZgVNt7ddJVOQ5RBUwhtts4 O/eFa4qWGBO/ak5P7MC+Gs8ThWAOMa6m/wu+G/+Z5glsnmtiVQaMgYIHw18mPKVu6E okHlTXsX46drF2qZJLZrvWQSxsYQMBlRaFIJCYXU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726730AbgHUUDj (ORCPT ); Fri, 21 Aug 2020 16:03:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:41152 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725831AbgHUUDi (ORCPT ); Fri, 21 Aug 2020 16:03:38 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (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 CFE7F2072D; Fri, 21 Aug 2020 20:03:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598040218; bh=yqh1mdXpcSLnQ7YmrqYC/jS5nW+Rhe7nFWcK9Uz415c=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=VwpreOGQ0XVfittG9uiZKaO2QGduoOPGTakL0fyyd5UQouefUlXlEqRUvyk0YRGpW UPrvpEBOSLctgylICILjSGmQd0rt2dagEc3p5E/mi1Ho/F001o2VnbBzKtp8UBzn8D twXYtNfvFKqRz98L9ZlGahczx9N43sfxeZHnqQaM= Date: Fri, 21 Aug 2020 13:03:37 -0700 From: Andrew Morton To: Yang Shi Cc: syzbot , Linux Kernel Mailing List , Linux MM , syzkaller-bugs@googlegroups.com, Jan Kara Subject: Re: KASAN: use-after-free Read in do_madvise Message-Id: <20200821130337.f4d1f5cd665ab149e1f43ed5@linux-foundation.org> In-Reply-To: References: <000000000000e44b7d05ad6624df@google.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; 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, 21 Aug 2020 10:15:45 -0700 Yang Shi wrote: > It looks the vma is gone. The below patch should be able to fix it: > > diff --git a/mm/madvise.c b/mm/madvise.c > index dd1d43cf026d..d4aa5f776543 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -289,9 +289,9 @@ static long madvise_willneed(struct vm_area_struct *vma, > */ > *prev = NULL; /* tell sys_madvise we drop mmap_lock */ > get_file(file); > - mmap_read_unlock(current->mm); > offset = (loff_t)(start - vma->vm_start) > + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); > + mmap_read_unlock(current->mm); > vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED); > fput(file); > mmap_read_lock(current->mm); Oh geeze. Can you please send this along as a real patch, cc:stable, Fixes: 692fe62433d4c? Please cc Jan!