linux-kernel - Re: [PATCH 12/14] sched: Add shared runqueue locking to __task_rq

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: <20250926103628.GE4067720@noisy.programming.kicks-ass.net>
Date: Fri, 26 Sep 2025 12:36:28 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Tejun Heo <tj@...nel.org>
Cc: linux-kernel@...r.kernel.org, mingo@...hat.com, juri.lelli@...hat.com,
	vincent.guittot@...aro.org, dietmar.eggemann@....com,
	rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de,
	vschneid@...hat.com, longman@...hat.com, hannes@...xchg.org,
	mkoutny@...e.com, void@...ifault.com, arighi@...dia.com,
	changwoo@...lia.com, cgroups@...r.kernel.org,
	sched-ext@...ts.linux.dev, liuwenfang@...or.com, tglx@...utronix.de
Subject: Re: [PATCH 12/14] sched: Add shared runqueue locking to
 __task_rq_lock()

On Thu, Sep 25, 2025 at 11:43:18AM -1000, Tejun Heo wrote:
> Yes, I was on a similar train of thought. The only reasonable way that I can
> think of for solving this for BPF managed tasks is giving each task its own
> inner sched lock, which makes sense as all sched operations (except for
> things like watchdog) are per-task and we don't really need wider scope
> locking.

Like I've said before; I really don't understand how that would be
helpful at all.

How can you migrate a task by holding a per-task lock?