From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752763AbaLEI3g (ORCPT ); Fri, 5 Dec 2014 03:29:36 -0500 Received: from mail-wi0-f173.google.com ([209.85.212.173]:58210 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751338AbaLEI3e (ORCPT ); Fri, 5 Dec 2014 03:29:34 -0500 From: Dmitry Monakhov To: Jeremiah Mahler , Stephen Rothwell Cc: linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, "Theodore Ts'o" Subject: Re: linux-next: Tree for Dec 4 In-Reply-To: <20141205005401.GA1279@hudson.localdomain> References: <20141204195928.4a5b93f4@canb.auug.org.au> <20141204233411.GA1223@hudson.localdomain> <20141205005401.GA1279@hudson.localdomain> User-Agent: Notmuch/0.18.1 (http://notmuchmail.org) Emacs/24.4.1 (x86_64-pc-linux-gnu) Date: Fri, 05 Dec 2014 11:29:03 +0300 Message-ID: <87sigu5wkw.fsf@openvz.org> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Jeremiah Mahler writes: > all, > > On Thu, Dec 04, 2014 at 03:34:11PM -0800, Jeremiah Mahler wrote: >> all, >>=20 >> On Thu, Dec 04, 2014 at 07:59:28PM +1100, Stephen Rothwell wrote: >> > Hi all, >> >=20 >> > Changes since 20141203: >> >=20 > [...] >> >=20 >> > --=20 >> > Cheers, >> > Stephen Rothwell sfr@canb.auug.org.au >> >=20 >> [...] >>=20 >> linux-next 20141204 is broken on all my machines, 20141203 worked fine. >>=20 >> They fail very early in the boot process and are unable to mount root. >> There are lots of "ext4_check_descriptors: Checksum for group ... >> failed" messages. >>=20 >> Any suggestions for where to start looking? >>=20 >> --=20 >> - Jeremiah Mahler > > I ran a bisect and found this patch to be faulty. > > commit fdfe073987619ec375da8d8a2701ab271d1b1339 > Author: Dmitry Monakhov > Date: Tue Dec 2 16:09:16 2014 -0500 >=20=20=20 > ext4: fix potential use after free during resize >=20=20=20=20=20=20=20 > We need some sort of synchronization while updating ->s_group_desc > because there are a lot of users which can access old ->s_group_desc > array after it was released. >=20=20=20=20=20=20=20 > Signed-off-by: Dmitry Monakhov > Signed-off-by: Theodore Ts'o + rcu_read_lock(); + gd_bh =3D *rcu_dereference(sbi->s_group_desc) + group_desc; + rcu_read_unlock();=20 Yes this is true crap. The only question is how it passed xfstess? > > --=20 > - Jeremiah Mahler --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBCgAGBQJUgWzQAAoJELhyPTmIL6kBkZYH/3BC7NzklZf/bqYf0lkPQdMp 9q8aY7ME5jTVFPopWTdgbMVOzWrFrDEedOjevnLDFSobjm2spM2OoWxXvyHGYhO4 4OBS//n8/CIubZuRTQzPQ8pmcRtDiW8F/NacbRzAH/KGe7h0221pU1pO0rLAyfih KjCGd+P8/qzrwiPr4amB0zTZtDFHiCJWbtrPkPNJ+zvvJEcSPzUqX+d9Rwm5N1zG zJEE0JdTryCY+hT0CIfKA1NiNFU5Q+woIR9IgEx4mj6uIpdSS9aD3pLxwtZTyVcf 2/PDTdqpqVOpJI7bA8zjRb1rAVfiRMhDyVFKjOZfU6CTQjkUqTy9mUlQe4FbPlU= =Vf97 -----END PGP SIGNATURE----- --=-=-=--