From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755415AbcBWVGB (ORCPT ); Tue, 23 Feb 2016 16:06:01 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41456 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755279AbcBWVF7 (ORCPT ); Tue, 23 Feb 2016 16:05:59 -0500 Message-ID: <1456261535.15241.96.camel@decadent.org.uk> Subject: Re: [STABLE] kernel oops which can be fixed by peterz's patches From: Ben Hutchings To: Mike Galbraith , Byungchul Park , Greg KH Cc: Peter Zijlstra , stable@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 23 Feb 2016 21:05:35 +0000 In-Reply-To: <1455678179.3531.15.camel@gmail.com> References: <20160105085211.GB3621@X58A-UD3R> <20160105091444.GZ6357@twins.programming.kicks-ass.net> <20160125072503.GB17836@X58A-UD3R> <20160216070837.GA5972@X58A-UD3R> <20160216084435.GQ6357@twins.programming.kicks-ass.net> <20160216174212.GB10487@kroah.com> <20160217001103.GB5972@X58A-UD3R> <20160217004139.GC3037@kroah.com> <20160217020008.GC5972@X58A-UD3R> <1455678179.3531.15.camel@gmail.com> Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-zqUd4EHcNkgSztAzWFuc" X-Mailer: Evolution 3.18.3-1 Mime-Version: 1.0 X-SA-Exim-Connect-IP: 92.40.248.141 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 --=-zqUd4EHcNkgSztAzWFuc Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2016-02-17 at 04:02 +0100, Mike Galbraith wrote: [...] > @stable: Kernels that predate SCHED_DEADLINE can use this simple (and tes= ted) > check in lieu of backport of the full 18 patch mainline treatment. >=20 > Signed-off-by: Mike Galbraith > --- > =C2=A0kernel/sched/fair.c |=C2=A0=C2=A0=C2=A0=C2=A09 +++++++++ > =C2=A01 file changed, 9 insertions(+) >=20 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -4008,6 +4008,7 @@ int can_migrate_task(struct task_struct > =C2=A0 =C2=A0* 2) cannot be migrated to this CPU due to cpus_allowed, or > =C2=A0 =C2=A0* 3) running (obviously), or > =C2=A0 =C2=A0* 4) are cache-hot on their current CPU. > + =C2=A0* 5) p->pi_lock is held. > =C2=A0 =C2=A0*/ > =C2=A0 if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu)) > =C2=A0 return 0; > @@ -4049,6 +4050,14 @@ int can_migrate_task(struct task_struct > =C2=A0 } > =C2=A0 > =C2=A0 /* > + =C2=A0* rt -> fair class change may be in progress.=C2=A0=C2=A0If we sn= eak in should > + =C2=A0* double_lock_balance() release rq->lock, and move the task, we w= ill > + =C2=A0* cause switched_to_fair() to meet a passed but no longer valid r= q. > + =C2=A0*/ > + if (raw_spin_is_locked(&p->pi_lock)) > + return 0; > + > + /* > =C2=A0 =C2=A0* Aggressive migration if: > =C2=A0 =C2=A0* 1) task is cache cold, or > =C2=A0 =C2=A0* 2) too many balance attempts have failed. Queued up for 3.2, thanks. Ben. --=20 Ben Hutchings Any smoothly functioning technology is indistinguishable from a rigged demo= . --=-zqUd4EHcNkgSztAzWFuc Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIVAwUAVszJoOe/yOyVhhEJAQq/cw/9EGEZlQAqqhMtY0ZZ8OijHnMD83qqLHOJ t/UO7ZvlLTZtG0HHXN2PB6GCQWAKZOlmk4Tq24BN8Y5lFFOKrqeV9OseRZWJkL0S bPfgmk85Rj0Xobgq09mK/IVmnR7o9/iQmN6mNIP6R02XjZHFwXFMtsh+ZqJFxbr+ rmH6bJkKOtyBQjGhmeR6igos8Su6ZZzO8b3qAuqRjnuXd+B5JYpxUUczAkFHpw5w VYYEiVu/g30Rd7xZH76h5LLicZ0qLgSeOXBLeGYK+QlbfrPto7y96bKUPMJsz6g+ ANdKdOAKdkCgvtCCOO02TmjkaZ0xvB3zY2ANUWKr2WBM0LZnM/AhUWYWwADkGKDM tTzI6a0/8gn8XHgHViOCEi+kp71AIEsoiHqmR0dvDuBzs6i21EjTsI0MKSOjFLpR i61e51ABGcgkNRwisVCIVjvuniEX+hyuLbR5aeKKECWWQ6ex5WJcWF2uc4O9aQZQ FqRLcrB/zhGEoLXff+MUNN8b+chh5EcCRH6OniiVAX311RUO7nCK5MAaXCAlXplo MuJZEslsfYqXSv0uXkVqz/4JDoQ+P+SjlrPm9XLpwOzv3x4pQ5rvaRJbvOOREOJJ 4V2ctyyHItWTTkHx8/+zViDW1JrB0tFM5z4RqC3smmxGeVSbo86iB1L+GKZFah0d 4NJoiQZ1OE4= =lJAh -----END PGP SIGNATURE----- --=-zqUd4EHcNkgSztAzWFuc--