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=-4.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 039A2C433E2 for ; Tue, 21 Jul 2020 04:32:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D77FE2080D for ; Tue, 21 Jul 2020 04:32:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=canb.auug.org.au header.i=@canb.auug.org.au header.b="X/TV8w6M" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726010AbgGUEcm (ORCPT ); Tue, 21 Jul 2020 00:32:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725294AbgGUEcl (ORCPT ); Tue, 21 Jul 2020 00:32:41 -0400 Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4484C061794; Mon, 20 Jul 2020 21:32:41 -0700 (PDT) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4B9m0f3SVBz9sRR; Tue, 21 Jul 2020 14:32:33 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=canb.auug.org.au; s=201702; t=1595305959; bh=w4Xy1OgH4XG7gHLmS4cliPvXoO5Wdfn568mqok1NPAY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=X/TV8w6MxL0/pdF660WExLs8QnY78mVX37uAVGP8YwhJmpVc/cd2ONOi2Eqb6xpqN 8tR+HCEEfKsyIDxQm6kgelL0AWd4IgISGHxncpZEa5u6u5LdL2iIP7HceBmK6Ftife aU+CnFPjx4DrzopWsIvXKh2T06M2tXo4Xd8IOuyo3wE3EDkoJ9wPN8EFNyEJLJRR+n Bxs0dH05MsfQaOLpj12TgdsobhkNKMKtnC9rYmrvCnGesLxVrk2kUC6mcGhyVJP96O SyuJ071yfB/ROvr8C9HSkQiq6MvwUfg6uZMtQynnRpBd7ed7ELBqVAuwIw9rwaRx3I ZkpE8y1ckMpkw== Date: Tue, 21 Jul 2020 14:32:33 +1000 From: Stephen Rothwell To: Qian Cai Cc: syzbot , Markus.Elfring@web.de, casey@schaufler-ca.com, dancol@google.com, hdanton@sina.com, jmorris@namei.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, stephen.smalley.work@gmail.com, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, yanfei.xu@windriver.com, linux-next@vger.kernel.org Subject: Re: KASAN: use-after-free Read in userfaultfd_release (2) Message-ID: <20200721143233.23c89f2a@canb.auug.org.au> In-Reply-To: <20200720155024.GC7354@lca.pw> References: <0000000000001bbb6705aa49635a@google.com> <000000000000cfc8ff05aa546b84@google.com> <20200717150540.GB31206@lca.pw> <20200720155024.GC7354@lca.pw> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/toEnhpP1bjnOrholb_30qUQ"; protocol="application/pgp-signature"; micalg=pgp-sha256 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org --Sig_/toEnhpP1bjnOrholb_30qUQ Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Hi all, On Mon, 20 Jul 2020 11:50:25 -0400 Qian Cai wrote: > > On Fri, Jul 17, 2020 at 11:05:41AM -0400, Qian Cai wrote: > > On Mon, Jul 13, 2020 at 08:34:06AM -0700, syzbot wrote: =20 > > > syzbot has bisected this bug to: > > >=20 > > > commit d08ac70b1e0dc71ac2315007bcc3efb283b2eae4 > > > Author: Daniel Colascione > > > Date: Wed Apr 1 21:39:03 2020 +0000 > > >=20 > > > Wire UFFD up to SELinux > > >=20 > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=3D14a79d= 13100000 > > > start commit: 89032636 Add linux-next specific files for 20200708 > > > git tree: linux-next > > > final crash: https://syzkaller.appspot.com/x/report.txt?x=3D16a79d= 13100000 > > > console output: https://syzkaller.appspot.com/x/log.txt?x=3D12a79d131= 00000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=3D64a250eba= bc6c320 > > > dashboard link: https://syzkaller.appspot.com/bug?extid=3D75867c44841= cb6373570 > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=3D13c4c8d= b100000 > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=3D12cbb68f1= 00000 > > >=20 > > > Reported-by: syzbot+75867c44841cb6373570@syzkaller.appspotmail.com > > > Fixes: d08ac70b1e0d ("Wire UFFD up to SELinux") > > >=20 > > > For information about bisection process see: https://goo.gl/tpsmEJ#bi= section =20 > >=20 > > This is rather easy to reproduce here, =20 >=20 > James, Stephen, can you drop this patch? Daniel's email was bounced, and = Viro > mentioned the patch could be quite bad, >=20 > https://lore.kernel.org/lkml/20200719165746.GJ2786714@ZenIV.linux.org.uk/ I have reverted that commit in linux-next today. --=20 Cheers, Stephen Rothwell --Sig_/toEnhpP1bjnOrholb_30qUQ Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEENIC96giZ81tWdLgKAVBC80lX0GwFAl8Wb+EACgkQAVBC80lX 0Gy4hQgAiOpVA7CVmdcLFC4iyaKl2GvE7+P5ZLPCSOXHu8si0xdVJwvtuOZiuGbT bSaV/lX5SM1e75PovM+I474GF8kxEPHDtvOA1tN6SUNgtuDTuIPtPbYD/a7anhSt 0FCmj2qQrEEAPgoO2o5Ccuq1RYkBA5P+stEYPzjWg/64OSNSP68R0vfjJfQYOUYU U9JyXx3psiVlS118+srxeLjjohVjjd3jN09cS+Xwp3AR6ltbdKFIz3uS2VO11pZZ 4lBgRFlqvLX6UE/aY8ky3+2zjSJbAJbZer6unQtoNvEOXNfVK8dDy0V/thZigMkH +ljiwrUO/tALZNF4ykpcS0Gt0626eA== =H813 -----END PGP SIGNATURE----- --Sig_/toEnhpP1bjnOrholb_30qUQ--