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Date: Wed, 13 May 2026 10:01:38 -1000
From: Tejun Heo <tj@kernel.org>
To: Samuele Mariotti <smariotti@disroot.org>
Cc: Andrea Righi <arighi@nvidia.com>, void@manifault.com,
	changwoo@igalia.com, sched-ext@lists.linux.dev,
	linux-kernel@vger.kernel.org,
	Paolo Valente <paolo.valente@unimore.it>
Subject: Re: [PATCH] sched_ext: Fix spurious WARN on stale ops_state in
 ops_dequeue()
Message-ID: <agTYojgRwDH67QMC@slm.duckdns.org>
References: <20260513095329.4029345-1-smariotti@disroot.org>
 <agSKJbtmpRPLgYJW@gpd4>
 <agSpf9QRx4zqhZxx@cachyos>
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In-Reply-To: <agSpf9QRx4zqhZxx@cachyos>

Hello,

On Wed, May 13, 2026 at 06:41:26PM +0200, Samuele Mariotti wrote:
> if (!(READ_ONCE(p->scx.flags) & SCX_TASK_IN_CUSTODY) &&
>      !WARN_ON_ONCE(retries++ >= 4)) {
>          cpu_relax();
>          goto retry;
> }

Let's not do the WARN and exit. We shouldn't get this wrong and if we get
this wrong, it's going to be obvious from lockup detectors. Can you please
add a comment explaining the retry condition tho?

Thanks.

-- 
tejun