From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754933AbbBPADc (ORCPT ); Sun, 15 Feb 2015 19:03:32 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:57358 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751546AbbBPADa (ORCPT ); Sun, 15 Feb 2015 19:03:30 -0500 Message-ID: <1424044997.23608.21.camel@decadent.org.uk> Subject: Re: [PATCH][v3.2 stable tree] dcache: Balance rcu_read_lock in have_submounts() From: Ben Hutchings To: Steven Rostedt Cc: LKML , stable , Al Viro Date: Mon, 16 Feb 2015 00:03:17 +0000 In-Reply-To: <20150212002850.146cf455@grimm.local.home> References: <20150117103806.0a7d3898@gandalf.local.home> <1423624537.2349.164.camel@decadent.org.uk> <20150212002850.146cf455@grimm.local.home> Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-BPjJkyN/ZhyPVmB6th8z" X-Mailer: Evolution 3.12.9-1+b1 Mime-Version: 1.0 X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-BPjJkyN/ZhyPVmB6th8z Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2015-02-12 at 00:28 -0500, Steven Rostedt wrote: > On Wed, 11 Feb 2015 03:15:37 +0000 > Ben Hutchings wrote: >=20 > > I've reviewed locking contexts in all three functions that I changed > > when backporting "deal with deadlock in d_walk()". It's actually worse > > than you say: > >=20 > > - We don't hold this_parent->d_lock at the 'positive' label in > > have_submounts(), but it is unlocked after 'rename_retry'. > > - There is an rcu_read_unlock() after the 'out' label in > > select_parent(), but it's not held at the 'goto out'. > >=20 > > Does the following patch work for you? >=20 > I booted the original 3.2 kernel 3 times and it succeeded once, and > crashed the other two. >=20 > I applied this patch and booted it 5 times, and it succeeded every time. >=20 > I removed the patch, and it crashed on the very next boot. >=20 > Thus, I'd say it seems to have fixed the issue for me. >=20 > Tested-by: Steven Rostedt [...] Thanks. Ben. --=20 Ben Hutchings Never attribute to conspiracy what can adequately be explained by stupidity= . --=-BPjJkyN/ZhyPVmB6th8z Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIVAwUAVOEzyue/yOyVhhEJAQoHSRAAmBDYHnaugKq7pgPHqM+Va4SsD2dVSMXx c2df2/Hc9jS72/D2fjz3E28FRh2+a0QcuyzEvHf9Wek+hdD1Hv+xMW47WsRwVocR 5RQ6m2KLU68PwihSeoDSEtVdYXFyY16Bt/I4mZcQ9hAX+HJYrXt3oeXNX2H3dQs8 ig8c6OB02x6kdboWkE7rvRS7MFNbMy9z1JZ/5tuhIyruC21LtKQoQkTLrmAfDw9j Gqj7egy5tx2HN15poNMiRkIkFwvUHSl+EDZVGprWk3txwME6OD5uceRvJyHz/f9z ww0fudxUvam/meKqhC0NvOn6sacsdzYkfSNBDNPVHhiGSAPElP4BmzG5xr+O174l tWGpDAnqF8pBZGyAibdZuckF7Q+wMOuHKvq42cyrj82u4CxWzUatLvCIiMZx/1EW ZA2ZkWRBvDKdXEa78XQk7d24DQ4zY9G5vYYxJBwrJfiH4MaJjTCf8SihHaeW8WZO ZW2wn1lnvwD224jzhzpRQ2lw8kq1A3439JByRYFgFGXWKHLKLkq5Hj7raT0RDcNd igSiHhyptepRTpO9gxksPOgNl+1gj6od6OycxN0IM8gR5tLQjhWIiH04vfExPFlz eckxzPtawMqy745+OdwtAVpshhcte3amHIRgE/JDkC/UOEyejX3HDCFjGtErZo8R tq+iuQhNdjg= =thmY -----END PGP SIGNATURE----- --=-BPjJkyN/ZhyPVmB6th8z--