From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752160AbYFRIRK (ORCPT ); Wed, 18 Jun 2008 04:17:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751167AbYFRIQ5 (ORCPT ); Wed, 18 Jun 2008 04:16:57 -0400 Received: from ms01.sssup.it ([193.205.80.99]:48457 "EHLO sssup.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750997AbYFRIQz (ORCPT ); Wed, 18 Jun 2008 04:16:55 -0400 X-Greylist: delayed 3598 seconds by postgrey-1.27 at vger.kernel.org; Wed, 18 Jun 2008 04:16:54 EDT Subject: NULL pointer dereference while setting sched_rt_period_us From: Dario Faggioli To: Michael Trimarchi , peterz@infradead.org, mingo@elte.hu, Linux Kernel Mailing List Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-OaJzNE1uS742PwRFSrI8" Date: Wed, 18 Jun 2008 09:18:38 +0200 Message-Id: <1213773519.5371.8.camel@Palanthas.Krynn> Mime-Version: 1.0 X-Mailer: Evolution 2.22.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-OaJzNE1uS742PwRFSrI8 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi all, When CONFIG_RT_GROUP_SCHED and =EF=BB=BFCONFIG_CGROUP_SCHED are enabled, wi= th: echo 10000 > /proc/sys/kernel/sched_rt_period_us We get this: BUG: unable to handle kernel NULL pointer dereference at 0000008c [ 947.682233] IP: [] __rt_schedulable+0x12/0x160 [ 947.683123] *pde =3D 00000000=20 [ 947.683782] Oops: 0000 [#1]=20 [ 947.684307] Modules linked in: [ 947.684308]=20 [ 947.684308] Pid: 2359, comm: bash Not tainted (2.6.26-rc6 #8) [ 947.684308] EIP: 0060:[] EFLAGS: 00000246 CPU: 0 [ 947.684308] EIP is at __rt_schedulable+0x12/0x160 [ 947.684308] EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 00000001 [ 947.684308] ESI: c0521db4 EDI: 00000001 EBP: c6cc9f00 ESP: c6cc9ed0 [ 947.684308] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 [ 947.684308] Process bash (pid: 2359, ti=3Dc6cc8000 task=3Dc7a54f00=20 task.ti=3Dc6cc8000) [ 947.684308] Stack: c0222790 00000000 080f8c08 c0521db4 c6cc9f00=20 00000001 00000000 00000000=20 [ 947.684308] c6cc9f9c 00000000 c0521db4 00000001 c6cc9f28=20 c0216d40 00000000 00000000=20 [ 947.684308] c6cc9f9c 000f4240 000e7ef0 ffffffff c0521db4=20 c79dfb60 c6cc9f58 c02af2cc=20 [ 947.684308] Call Trace: [ 947.684308] [] ? do_proc_dointvec_conv+0x0/0x50 [ 947.684308] [] ? sched_rt_handler+0x80/0x110 [ 947.684308] [] ? proc_sys_call_handler+0x9c/0xb0 [ 947.684308] [] ? proc_sys_write+0x1a/0x20 [ 947.684308] [] ? vfs_write+0x96/0x160 [ 947.684308] [] ? proc_sys_write+0x0/0x20 [ 947.684308] [] ? sys_write+0x3d/0x70 [ 947.684308] [] ? sysenter_past_esp+0x6a/0x91 [ 947.684308] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D [ 947.684308] Code: 24 04 e8 62 b1 0e 00 89 c7 89 f8 8b 5d f4 8b 75 f8 8b 7d fc 89 ec 5d c3 90 55 89 e5 57 56 53 83 ec 24 89 45 ec 89 55 e4 89 4d e8 <8b> b8 8c 00 00 00 85 ff 0f 84 c9 00 00 00 8b 57 24 39 55 e8 8b=20 [ 947.684308] EIP: [] __rt_schedulable+0x12/0x160 SS:ESP =20 0068:c6cc9ed0 We think the following patch solves the issue. Hope this is of some help. Regards, Dario Faggioli Signed-off-by: Dario Faggioli Signed-off-by: Michael Trimarchi --- diff --git a/kernel/sched.c b/kernel/sched.c index eaf6751..7205e25 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8348,7 +8348,7 @@ static unsigned long to_ratio(u64 period, u64 runtime) #ifdef CONFIG_CGROUP_SCHED static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) { - struct task_group *tgi, *parent =3D tg->parent; + struct task_group *tgi, *parent =3D tg ? tg->parent : NULL; unsigned long total =3D 0; =20 if (!parent) { --=20 <> (Raistlin Majere, DragonLance Chronicles -Dragons of Spring Drawning-) ---------------------------------------------------------------------- Dario Faggioli GNU/Linux Registered User: #340657 Web: http://www.linux.it/~raistlin Blog: http://blog.linux.it/raistlin SIP Account: dario.faggioli@sipproxy.wengo.fr or raistlin@ekiga.net Jabber Account: dario.faggioli@jabber.org/WengoPhone GnuPG Key ID: 4DC83AC4 GnuPG Key Fingerprint: 2A78 AD5D B9CF A082 0836 08AD 9385 DA04 4DC8 3AC4 --=-OaJzNE1uS742PwRFSrI8 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEABECAAYFAkhYts4ACgkQk4XaBE3IOsQNiACffcPctmEZV/ttZD3F/VYHY0n7 HI0AmwZNbUIW+YEHCcedI6aL2YRirKEl =dIFn -----END PGP SIGNATURE----- --=-OaJzNE1uS742PwRFSrI8--