From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 11CB63D6465 for ; Tue, 28 Apr 2026 09:44:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777369453; cv=none; b=UkegFp8usRdSWIx0ScFznvio+Cf7Tvjhc4yFL+wsjjaqoATkcioGw8TUGLit/L2aRdD899WvZ3YjcUxNKNSroUYP2LVXpI7nIkwuE91NJt25GSelOZrONAtmxH40CfS1o8cN9KKMBgjqTWK6gLIJ3oanespPtmgxiIFwntmRN58= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777369453; c=relaxed/simple; bh=w0Sb5B2ZHsKqUn9vUF+YMEU+aChjG0KKin+vHPUhpMg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JWQ6KCfYqNkNe2uY4UrxyP7mffRhDEn1IZYfFVCPQ0Mm5YFBlAXfATw4gc9/A4ljSDF0b/Zno/fv0lKwyzHDeHcLQ9iaHA79WN+ilhjyNGuaPJ3burFXIQ9n/ALhIn5uRkIVS6/qd55joxEecuNn0BWKXb30jk9aRRMWqZoMDu8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=a1nayzkF; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="a1nayzkF" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=pVNF0JxTFvAHw/Z3Uh2HPtzy1YWNKNBEHV+Czm1ol00=; b=a1nayzkFooh7LcV3wcIWtoLZji UzXFfcWHEbvDnNMr6n1SB/Kw/nxjc21DzUyPvdq+qFL/sysoRr8B4nkFZZ6EUlh13CY9EdtBGpyVZ bLWE5PItobULsn2Ob4fLo8d9Y8P4VFA2Gu7Efj9mxboG7ejKL+8giZRb2kUtq6tHPqOlllIalYaoo r8aVtjEgUdk8UFt4+vEVlnLh46un32k4Wkmaj9bhY6qxyTIaUMPUq4JECYWsVDUUWcflQXnGGt83K nQFkAEXn1GpSSA4lo0Uq+XeIRtImbAhhPnbwgpqXLkwqqyjod7VibDnOo3w1wZJki2RI3whSs1lA1 eeDyxBWg==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1wHeyw-00000002ccX-0SHp; Tue, 28 Apr 2026 09:43:54 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 8832F301CEB; Tue, 28 Apr 2026 11:43:53 +0200 (CEST) Date: Tue, 28 Apr 2026 11:43:53 +0200 From: Peter Zijlstra To: John Stultz Cc: LKML , Vineeth Pillai , Sonam Sanju , Sean Christopherson , Kunwu Chan , Tejun Heo , Joel Fernandes , Qais Yousef , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Valentin Schneider , Steven Rostedt , Will Deacon , Waiman Long , Boqun Feng , "Paul E. McKenney" , Metin Kaya , Xuewen Yan , K Prateek Nayak , Thomas Gleixner , Daniel Lezcano , Suleiman Souhlal , kuyo chang , hupu , kernel-team@android.com Subject: Re: [PATCH 1/2] sched: proxy-exec: Close race causing workqueue work being delayed Message-ID: <20260428094353.GB1026330@noisy.programming.kicks-ass.net> References: <20260427183848.698551-1-jstultz@google.com> <20260427183848.698551-2-jstultz@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260427183848.698551-2-jstultz@google.com> On Mon, Apr 27, 2026 at 06:38:40PM +0000, John Stultz wrote: > kernel/sched/core.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index da20fb6ea25ae..5f684caefd8b2 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -7097,6 +7097,17 @@ static void __sched notrace __schedule(int sched_mode) > try_to_block_task(rq, prev, &prev_state, > !task_is_blocked(prev)); > switch_count = &prev->nvcsw; > + } else if (preempt && prev->blocked_on) { > + /* > + * If we are SM_PREEMPT, we may have interrupted > + * after blocked_on was set, before schedule() > + * was run, preventing workques from running. So workqueues > + * clear blocked_on and mark task RUNNING so it > + * can be reselected to run and complete its > + * logic > + */ > + WRITE_ONCE(prev->__state, TASK_RUNNING); > + clear_task_blocked_on(prev, NULL); > } > > pick_again: *groan*, this feels wrong. Preemption should never touch state. Let me try and wake up and make sense of this.