From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from james.kirk.hungrycats.org ([174.142.39.145]:39260 "EHLO james.kirk.hungrycats.org" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750900AbcJIELp (ORCPT ); Sun, 9 Oct 2016 00:11:45 -0400 Date: Sun, 9 Oct 2016 00:11:22 -0400 From: Zygo Blaxell To: linux-btrfs@vger.kernel.org Cc: Chris Mason Subject: Re: btrfs rare silent data corruption with kernel data leak (updated with some bisection results) Message-ID: <20161009041122.GV21290@hungrycats.org> References: <20160921045556.GN21290@hungrycats.org> <20161008061008.GT21290@hungrycats.org> <20161008070200.GU21290@hungrycats.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="CSNFvL6ilyiKL/Hs" In-Reply-To: <20161008070200.GU21290@hungrycats.org> Sender: linux-btrfs-owner@vger.kernel.org List-ID: --CSNFvL6ilyiKL/Hs Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Oct 08, 2016 at 03:02:00AM -0400, Zygo Blaxell wrote: > On Sat, Oct 08, 2016 at 02:10:08AM -0400, Zygo Blaxell wrote: > [...] > > The "write half" of the bug seems to appear first somewhere between v3.8 > > and v3.9. I have not been able to reproduce it with v3.8.13, v3.7.10, = or > > v3.6.11. I can reproduce it in v3.9.11, v3.12.64, and v3.18.13..v4.7.5. >=20 > After six more iterations of the 'repro' script, I can reproduce "write > half" on 3.8.13. >=20 > Bisection is hard. Bisecting ancient bugs even more so. I increased the number of iterations of the 'repro' script to 100, although in practice no more than 20 are required. With this test case, I can find the bug in kernels as early as v3.5.7. v3.0..v3.4 crash before they complete one run of the 'repro' script. Earlier kernels don't work with the userspace on my testing machine, and going back more than four years is not worth the effort IMHO. At the other end of the timeline, I also reproduced this bug on 4.8.1. --CSNFvL6ilyiKL/Hs Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlf5w2oACgkQgfmLGlazG5xzeQCfRreGUInUlM1IcFJZJ5ShxiLY EhEAn30i1mFsvB7YRTcwTxMnEf+V6Av6 =aqaB -----END PGP SIGNATURE----- --CSNFvL6ilyiKL/Hs--