From: Eugene Syromiatnikov <esyr@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: joel@joelfernandes.org, chris.hyser@oracle.com,
joshdon@google.com, mingo@kernel.org, vincent.guittot@linaro.org,
valentin.schneider@arm.com, mgorman@suse.de,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
Christian Brauner <christian.brauner@ubuntu.com>,
ldv@strace.io
Subject: Re: [PATCH] sched: Fix Core-wide rq->lock for uninitialized CPUs
Date: Thu, 19 Aug 2021 18:19:22 +0200 [thread overview]
Message-ID: <20210819161922.GA18087@asgard.redhat.com> (raw)
In-Reply-To: <YR473ZGeKqMs6kw+@hirez.programming.kicks-ass.net>
On Thu, Aug 19, 2021 at 01:09:17PM +0200, Peter Zijlstra wrote:
> On Wed, Aug 18, 2021 at 01:17:34AM +0200, Eugene Syromiatnikov wrote:
> > On Tue, Aug 17, 2021 at 05:52:43PM +0200, Peter Zijlstra wrote:
> > > Urgh... lemme guess, your HP BIOS is funny and reports more possible
> > > CPUs than you actually have resulting in cpu_possible_mask !=
> > > cpu_online_mask. Alternatively, you booted with nr_cpus= or something
> > > daft like that.
> >
> > Yep, it seems to be the case:
> >
> > # cat /sys/devices/system/cpu/possible
> > 0-7
> > # cat /sys/devices/system/cpu/online
> > 0-3
> >
>
> I think the below should work... can you please verify?
Yes, it no longer oops'es now, thank you!
# cat /sys/devices/system/cpu/possible
0-7
# cat /sys/devices/system/cpu/online
0-3
# ./prctl-sched-core-oops-repro
Iteration 0 status: 0
Iteration 1 status: 0
# ../src/strace -fvq -eprctl,clone,setsid -esignal=none ./prctl-sched-core-oops-repro
clone(child_stack=NULL, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7f510b1c7890) = 108328
[pid 108328] setsid() = 108328
[pid 108328] +++ exited with 0 +++
Iteration 0 status: 0
prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, 108324, 0x2 /* PIDTYPE_PGID */, NULL) = 0
clone(child_stack=NULL, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7f510b1c7890) = 108329
[pid 108329] setsid() = 108329
[pid 108329] +++ exited with 0 +++
Iteration 1 status: 0
prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, 108324, 0x2 /* PIDTYPE_PGID */, NULL) = 0
+++ exited with 0 +++
> ---
> Subject: sched: Fix Core-wide rq->lock for uninitialized CPUs
>
> Eugene tripped over the case where rq_lock(), as called in a
> for_each_possible_cpu() loop came apart because rq->core hadn't been
> setup yet.
>
> This is a somewhat unusual, but valid case.
>
> Rework things such that rq->core is initialized to point at itself. IOW
> initialize each CPU as a single threaded Core. CPU online will then join
> the new CPU (thread) to an existing Core where needed.
>
> For completeness sake, have CPU offline fully undo the state so as to
> not presume the topology will match the next time it comes online.
>
> Fixes: 9edeaea1bc45 ("sched: Core-wide rq->lock")
> Reported-by: Eugene Syromiatnikov <esyr@redhat.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Eugene Syromiatnikov <esyr@redhat.com>
next prev parent reply other threads:[~2021-08-19 16:19 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 12:04 [PATCH 00/19] sched: Core Scheduling Peter Zijlstra
2021-04-22 12:05 ` [PATCH 01/19] sched/fair: Add a few assertions Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-05-13 8:56 ` Ning, Hongyu
2021-04-22 12:05 ` [PATCH 02/19] sched: Provide raw_spin_rq_*lock*() helpers Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 03/19] sched: Wrap rq::lock access Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 04/19] sched: Prepare for Core-wide rq->lock Peter Zijlstra
2021-04-24 1:22 ` Josh Don
2021-04-26 8:31 ` Peter Zijlstra
2021-04-26 22:21 ` Josh Don
2021-04-27 17:10 ` Don Hiatt
2021-04-27 23:35 ` Josh Don
2021-04-28 1:03 ` Aubrey Li
2021-04-28 6:05 ` Aubrey Li
2021-04-28 10:57 ` Aubrey Li
2021-04-28 16:41 ` Don Hiatt
2021-04-29 20:48 ` Josh Don
2021-04-29 21:09 ` Don Hiatt
2021-04-29 23:22 ` Josh Don
2021-04-30 16:18 ` Don Hiatt
2021-04-30 8:26 ` Aubrey Li
2021-04-28 16:04 ` Don Hiatt
2021-04-27 23:30 ` Josh Don
2021-04-28 9:13 ` Peter Zijlstra
2021-04-28 10:35 ` Aubrey Li
2021-04-28 11:03 ` Peter Zijlstra
2021-04-28 14:18 ` Paul E. McKenney
2021-04-29 20:11 ` Josh Don
2021-05-03 19:17 ` Peter Zijlstra
2021-04-28 7:13 ` Peter Zijlstra
2021-04-28 6:02 ` Aubrey Li
2021-04-29 8:03 ` Aubrey Li
2021-04-29 20:39 ` Josh Don
2021-04-30 8:20 ` Aubrey Li
2021-04-30 8:48 ` Josh Don
2021-04-30 14:15 ` Aubrey Li
2021-05-04 7:38 ` Peter Zijlstra
2021-05-05 16:20 ` Don Hiatt
2021-05-06 10:25 ` Peter Zijlstra
2021-05-07 9:50 ` [PATCH v2 " Peter Zijlstra
2021-05-08 8:07 ` Aubrey Li
2021-05-12 9:07 ` Peter Zijlstra
2021-04-22 12:05 ` [PATCH 05/19] sched: " Peter Zijlstra
2021-05-07 9:50 ` [PATCH v2 " Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 06/19] sched: Optimize rq_lockp() usage Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 07/19] sched: Allow sched_core_put() from atomic context Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 08/19] sched: Introduce sched_class::pick_task() Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 09/19] sched: Basic tracking of matching tasks Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 10/19] sched: Add core wide task selection and scheduling Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 11/19] sched/fair: Fix forced idle sibling starvation corner case Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Vineeth Pillai
2021-04-22 12:05 ` [PATCH 12/19] sched: Fix priority inversion of cookied task with sibling Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Joel Fernandes (Google)
2021-04-22 12:05 ` [PATCH 13/19] sched/fair: Snapshot the min_vruntime of CPUs on force idle Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Joel Fernandes (Google)
2021-04-22 12:05 ` [PATCH 14/19] sched: Trivial forced-newidle balancer Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 15/19] sched: Migration changes for core scheduling Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Aubrey Li
2021-04-22 12:05 ` [PATCH 16/19] sched: Trivial core scheduling cookie management Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 17/19] sched: Inherit task cookie on fork() Peter Zijlstra
2021-05-10 16:06 ` Joel Fernandes
2021-05-10 16:22 ` Chris Hyser
2021-05-10 20:47 ` Joel Fernandes
2021-05-10 21:38 ` Chris Hyser
2021-05-12 9:05 ` Peter Zijlstra
2021-05-12 20:20 ` Josh Don
2021-05-12 21:07 ` Don Hiatt
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 18/19] sched: prctl() core-scheduling interface Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Chris Hyser
2021-06-14 23:36 ` [PATCH 18/19] " Josh Don
2021-06-15 11:31 ` Joel Fernandes
2021-08-05 16:53 ` Eugene Syromiatnikov
2021-08-05 17:00 ` Peter Zijlstra
2021-08-17 15:15 ` Eugene Syromiatnikov
2021-08-17 15:52 ` Peter Zijlstra
2021-08-17 23:17 ` Eugene Syromiatnikov
2021-08-19 11:09 ` [PATCH] sched: Fix Core-wide rq->lock for uninitialized CPUs Peter Zijlstra
2021-08-19 15:50 ` Tao Zhou
2021-08-19 16:19 ` Eugene Syromiatnikov [this message]
2021-08-20 0:18 ` Josh Don
2021-08-20 10:02 ` Peter Zijlstra
2021-08-23 9:07 ` [tip: sched/urgent] " tip-bot2 for Peter Zijlstra
2021-04-22 12:05 ` [PATCH 19/19] kselftest: Add test for core sched prctl interface Peter Zijlstra
2021-05-12 10:28 ` [tip: sched/core] " tip-bot2 for Chris Hyser
2021-04-22 16:43 ` [PATCH 00/19] sched: Core Scheduling Don Hiatt
2021-04-22 17:29 ` Peter Zijlstra
2021-04-30 6:47 ` Ning, Hongyu
2021-05-06 10:29 ` Peter Zijlstra
2021-05-06 12:53 ` Ning, Hongyu
2021-05-07 18:02 ` Joel Fernandes
2021-05-10 16:16 ` Vincent Guittot
2021-05-11 7:00 ` Vincent Guittot
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210819161922.GA18087@asgard.redhat.com \
--to=esyr@redhat.com \
--cc=chris.hyser@oracle.com \
--cc=christian.brauner@ubuntu.com \
--cc=joel@joelfernandes.org \
--cc=joshdon@google.com \
--cc=ldv@strace.io \
--cc=linux-kernel@vger.kernel.org \
--cc=mgorman@suse.de \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=valentin.schneider@arm.com \
--cc=vincent.guittot@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).