From: Yury Norov <yury.norov@gmail.com>
To: Christian Loehle <christian.loehle@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Mark Rutland <Mark.Rutland@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Juri Lelli <juri.lelli@redhat.com>,
Valentin Schneider <vschneid@redhat.com>
Subject: Re: PATCH] sched: Fix sched_numa_find_nth_cpu() if mask offline
Date: Wed, 3 Sep 2025 12:15:17 -0400 [thread overview]
Message-ID: <aLhplQVvIJqWo1ac@yury> (raw)
In-Reply-To: <1ae868cf-470b-44d8-bda3-20a64dedd8b8@arm.com>
On Wed, Sep 03, 2025 at 04:48:32PM +0100, Christian Loehle wrote:
> sched_numa_find_nth_cpu() uses a bsearch to look for the 'closest'
> CPU in sched_domains_numa_masks and given cpus mask. However they
> might not intersect if all CPUs in the cpus mask are offline. bsearch
> will return NULL in that case, bail out instead of dereferencing a
> bogus pointer.
>
> The previous behaviour lead to this bug when using maxcpus=4 on an
> rk3399 (LLLLbb) (i.e. booting with all big CPUs offline):
Thanks! Scheduling for -rc5.
prev parent reply other threads:[~2025-09-03 16:15 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-03 15:48 PATCH] sched: Fix sched_numa_find_nth_cpu() if mask offline Christian Loehle
2025-09-03 16:15 ` Yury Norov [this message]
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