linux-kernel - Re: [PATCH] sched/fair: Add null pointer check to pick_next

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: <20250416124442.GC6580@noisy.programming.kicks-ass.net>
Date: Wed, 16 Apr 2025 14:44:42 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Rik van Riel <riel@...riel.com>
Cc: Chris Mason <clm@...a.com>, Pat Cody <pat@...cody.io>, 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, linux-kernel@...r.kernel.org,
	patcody@...a.com, kernel-team@...a.com,
	Breno Leitao <leitao@...ian.org>
Subject: Re: [PATCH] sched/fair: Add null pointer check to pick_next_entity()

On Tue, Apr 15, 2025 at 10:02:35AM +0200, Peter Zijlstra wrote:
> On Mon, Apr 14, 2025 at 03:57:42PM -0400, Rik van Riel wrote:
> > On Wed, 2025-04-02 at 10:22 +0200, Peter Zijlstra wrote:
> > > 
> > > Please confirm what the reason for overflow is.
> > > 
> > Running a large enough sample size has its benefits.
> > 
> > We have hit 3 out of the 4 warnings below.
> > 
> > The only one we did not hit is the cfs_rq->avg_load != avg_load
> > warning.
> 
> Fair enough, that one really isn't hard.
> 
> > Most of the time we seem to hit the warnings from the
> > code that removes tasks from the runqueue, 
> 
> *blink*..

Which warning is getting hit on removal? The avg_vruntime mismatch?

Also, which removal path? schedule()'s block path, or migration like?