From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754551Ab1HGSWi (ORCPT ); Sun, 7 Aug 2011 14:22:38 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:59032 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754421Ab1HGSWh (ORCPT ); Sun, 7 Aug 2011 14:22:37 -0400 Subject: Re: [Stable-review] [07/55] SUNRPC: Fix a race between work-queue and rpc_killall_tasks From: Ben Hutchings To: Greg KH Cc: linux-kernel@vger.kernel.org, stable@kernel.org, Trond Myklebust , akpm@linux-foundation.org, torvalds@linux-foundation.org, stable-review@kernel.org, alan@lxorguk.ukuu.org.uk In-Reply-To: <20110806000249.573906795@clark.kroah.org> References: <20110806000249.573906795@clark.kroah.org> Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-hDw9Yow7oUKyxYXNZnRQ" Date: Sun, 07 Aug 2011 18:38:01 +0100 Message-ID: <1312738681.2591.1024.camel@deadeye> Mime-Version: 1.0 X-Mailer: Evolution 2.32.3 X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 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 --=-hDw9Yow7oUKyxYXNZnRQ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, 2011-08-05 at 17:01 -0700, Greg KH wrote: > 2.6.32-longterm review patch. If anyone has any objections, please let u= s know. >=20 > ------------------ >=20 > From: Trond Myklebust >=20 > commit b55c59892e1f3b6c7d4b9ccffb4263e1486fb990 upstream. >=20 > Since rpc_killall_tasks may modify the rpc_task's tk_action field > without any locking, we need to be careful when dereferencing it. [...] This isn't nearly careful enough to avoid races. You must at least use the ACCESS_ONCE macro, otherwise the compiler can just optimise away the local variable this introduces. Ben. --=-hDw9Yow7oUKyxYXNZnRQ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIVAwUATj7NeOe/yOyVhhEJAQo7Fg/+Pul3rkBiO3WzsIW/Q0vKVcUNNwirMVzQ VSAqWVm6rNP9G3cF/xnMnglWuJL/Gzyy/KuDjKK5hHBWh6IUdwYFVvCOtRB6iyYd DoRQy1IXDyzcgtdJK/2uq0MC0aaebxSCiZ6k18JoLBDcD0CJK/4n4PeQEfOb5Ym6 H3YRRx2gPCwsdo4+dbN/jWKAZdwGVJ2BZOC9Waq2mEDe7EKG8/q8FHbCF+DJE2YW 529ZQq5joObWvKd+PR5Ab7m0yVkuSPqfjeVTjhxg1nlJ3L65KHMtEiGt0eVgQEr3 rdgNxQ75C0zzZyfsMUqLViZBY+tf8lm9Vs8epNwpUv/7xoooU0K2F9UPQCuBv1vm 5EhNQoGOLKLCUMihypovjeQ0bencTw7+6q54oofAgGTuRP1VTICmeOwswarPi2UE q9fOlVWidBStNPgtaBLHV3O4serX0eao2ZawnQOgOw1/Qomnnj3cdhUbbmzNpsue hnthjBN8uLcd6cONBukORMtfcTdtUWu9LdR95qtZiXk1kHHOYH65eIUZqz6gq1Ap KlIJn9v+JBx5JaZPPzpExkPMrgkfgkXiGCFiu/0jc2bvknpVnFr/4CGkwTuOvGaj Xwh9cjZi4wWfxWCQViIxS4Zfg7A4Rji2jewGWekTTf8wiiwrvf1024UvbOhgvfxu Agnyx4IoT+0= =3pvt -----END PGP SIGNATURE----- --=-hDw9Yow7oUKyxYXNZnRQ--