linux-kernel - Re: [PATCH 6.12 000/122] 6.12.11-rc1 review

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <bfc6d9c18eaa856cddb062ebc07c398a16d91353.camel@gmx.de>
Date: Tue, 28 Jan 2025 12:46:07 +0100
From: Mike Galbraith <efault@....de>
To: Ron Economos <re@...z.net>, Peter Zijlstra <peterz@...radead.org>, Arnd
	Bergmann <arnd@...db.de>
Cc: Naresh Kamboju <naresh.kamboju@...aro.org>, Greg Kroah-Hartman
 <gregkh@...uxfoundation.org>, stable@...r.kernel.org,
 patches@...ts.linux.dev,  linux-kernel@...r.kernel.org, Linus Torvalds
 <torvalds@...ux-foundation.org>,  Andrew Morton
 <akpm@...ux-foundation.org>, Guenter Roeck <linux@...ck-us.net>, shuah
 <shuah@...nel.org>,  patches@...nelci.org, lkft-triage@...ts.linaro.org,
 Pavel Machek <pavel@...x.de>,  Jon Hunter <jonathanh@...dia.com>, Florian
 Fainelli <f.fainelli@...il.com>, Sudip Mukherjee
 <sudipm.mukherjee@...il.com>, srw@...dewatkins.net, rwarsow@....de, Conor
 Dooley <conor@...nel.org>, hargar@...rosoft.com, Mark Brown
 <broonie@...nel.org>,  Anders Roxell <anders.roxell@...aro.org>, Vincent
 Guittot <vincent.guittot@...aro.org>, Dan Carpenter
 <dan.carpenter@...aro.org>
Subject: Re: [PATCH 6.12 000/122] 6.12.11-rc1 review

On Wed, 2025-01-22 at 03:11 -0800, Ron Economos wrote:
> On 1/22/25 02:59, Peter Zijlstra wrote:
> > On Wed, Jan 22, 2025 at 11:56:13AM +0100, Arnd Bergmann wrote:
> > > On Wed, Jan 22, 2025, at 11:04, Naresh Kamboju wrote:
> > > > On Tue, 21 Jan 2025 at 23:28, Greg Kroah-Hartman
> > > > <gregkh@...uxfoundation.org> wrote:
> > > > 0000000000000000
> > > > <4>[  160.712071] Call trace:
> > > > <4>[ 160.712597] place_entity (kernel/sched/fair.c:5250 (discriminator 1))
> > > > <4>[ 160.713221] reweight_entity (kernel/sched/fair.c:3813)
> > > > <4>[ 160.713802] update_cfs_group (kernel/sched/fair.c:3975 (discriminator 1))
> > > > <4>[ 160.714277] dequeue_entities (kernel/sched/fair.c:7091)
> > > > <4>[ 160.714903] dequeue_task_fair (kernel/sched/fair.c:7144 (discriminator 1))
> > > > <4>[ 160.716502] move_queued_task.isra.0 (kernel/sched/core.c:2437
> > > > (discriminator 1))
> > > I don't see anything that immediately sticks out as causing this,
> > > but I do see five scheduler patches backported in stable-rc
> > > on top of v6.12.8, these are the original commits:
> > >
> > > 66951e4860d3 ("sched/fair: Fix update_cfs_group() vs DELAY_DEQUEUE")
> > This one reworks reweight_entity(), but I've been running with that on
> > top of 13-rc6 for a week or so and not seen this.
>
> The offending commit is 6d71a9c6160479899ee744d2c6d6602a191deb1f
> "sched/fair: Fix EEVDF entity placement bug causing scheduling lag"
>
> It works fine on 6.13, at least on RISC-V (which is the only arch I test).

Seems 6.13 is gripe free thanks to it containing 4423af84b297.

I stumbled upon a reproducer for my x86_64 desktop box: all I need do
is fire up a kvm guest in an enterprise configured host.  That inspires
libvirt goop to engage group scheduling, splat follows instantly.

Back 4423af84b297 out of 6.13, it starts griping, add it to a 6.12 tree
containing 6d71a9c61604, it stops doing so.

> It's already been reverted and 6.12.11-rc2 has been pushed out.

So stable should perhaps take 4423af84b297 along with 6d71a9c61604?

	-Mike