From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932911Ab1LFBmb (ORCPT ); Mon, 5 Dec 2011 20:42:31 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:63111 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932809Ab1LFBmZ (ORCPT ); Mon, 5 Dec 2011 20:42:25 -0500 X-Authority-Analysis: v=2.0 cv=Xd0LPfF5 c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=vhdKIqpQuCYA:10 a=EYO6vQuAaOcA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=20KFwNOVAAAA:8 a=VwQbUJbxAAAA:8 a=meVymXHHAAAA:8 a=63xn6-QBRweX3glTVUoA:9 a=QEXdDO2ut3YA:10 a=jEp0ucaQiEUA:10 a=jeBq3FmKZ4MA:10 a=jviTgBqhR1iXBv9GQ3EA:9 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-Id: <20111206014222.808638750@goodmis.org> User-Agent: quilt/0.48-1 Date: Mon, 05 Dec 2011 20:41:14 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , stable@vger.kernel.org, Peter Zijlstra , Jason Baron , Gleb Natapov Subject: [PATCH 4/6] jump_label: jump_label_inc may return before the code is patched References: <20111206014110.079874115@goodmis.org> Content-Disposition: inline; filename=0004-jump_label-jump_label_inc-may-return-before-the-code.patch Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="00GvhwF7k39YY" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --00GvhwF7k39YY Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable From: Gleb Natapov If cpu A calls jump_label_inc() just after atomic_add_return() is called by cpu B, atomic_inc_not_zero() will return value greater then zero and jump_label_inc() will return to a caller before jump_label_update() finishes its job on cpu B. Link: http://lkml.kernel.org/r/20111018175551.GH17571@redhat.com Cc: stable@vger.kernel.org Cc: Peter Zijlstra Acked-by: Jason Baron Signed-off-by: Gleb Natapov Signed-off-by: Steven Rostedt --- kernel/jump_label.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/kernel/jump_label.c b/kernel/jump_label.c index bbdfe2a..66ff710 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -66,8 +66,9 @@ void jump_label_inc(struct jump_label_key *key) return; =20 jump_label_lock(); - if (atomic_add_return(1, &key->enabled) =3D=3D 1) + if (atomic_read(&key->enabled) =3D=3D 0) jump_label_update(key, JUMP_LABEL_ENABLE); + atomic_inc(&key->enabled); jump_label_unlock(); } =20 --=20 1.7.7.3 --00GvhwF7k39YY 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) iQIcBAABAgAGBQJO3XL/AAoJEIy3vGnGbaoAgd0QAIsffRY/SBfbOq8fGdw2/09g bQ/m7/QzgcDQUuXkcHl85mJbiSF6sz+7Y4pdnRD/4iGfxskLPxoVrbqjN0HpinwR 285dkAtuh89b7g+LulKPPxaHuWNC1enOgQ5zNgOXuIGhwTc6GIxZyXXoYQFR1tJH kq3OiYMb/Bpm0Fa4CO6TWllqgD2FroxiO2uUYX8X3yNr9RFoT90Ct64ehdsvgHtm YTDRHg1pstagBF0lbjMB448Cs+Oi4llDRJH+7KFKQ2Bbx5j9z8aNO1Bi8D1MLG3e ASJtjOleG0bWQoamb3jhHprJbwP+A9LENPXLlys/kZHBRl7IMzNPP11Qn4Ejf84W LDJZb4io757ug86T8EW1yBl8HRM9t72yssWPgLqZd/LJfFDPKO2Kf2nVEv5cAU/4 s+bRvOdpUDg+qGA1PnNbb5U2EQpfIHYHXwQx+Mok4kEYwX7klLG8WWg5218JRx6d DlOcELDDiRzvpD4GDZmFlpAm+TJfUPkXtHrTBt+oFWzEMRsXQppqj3k+He2dLems 3rH42AqJaM/ZYjLDBXEdh3kJgOWc19TnpbDIiEirzq3ZSAe8ImLlzEKXLN0PYEKo 3dkswfHY3tNtQbjkKOcbqwV0XdZmfO2gZDybycehXuFCrr3NKjQT0uV51NQcAj7c iweolK71YeLX/SYcjU5x =DlTs -----END PGP SIGNATURE----- --00GvhwF7k39YY--