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 E87BD130AC8 for ; Mon, 9 Dec 2024 10:55:20 +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=1733741723; cv=none; b=iButvET7EQoHx9acvvoYW3Q4ZPS7XUYiv6alNS24WNtybhoGq88S3LD9qxEZLBshqqNGhdW+4E9S5xN4ja1LCsP3wgzb6tniX9cupQnfS0ZeaTZ74L/1EgqCpHn8gBqcTS+S+UW2UmsjpeEc+krkUnVHFkxRST98GHquZmDjg4A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733741723; c=relaxed/simple; bh=cTzwRwB0TyD+Ekx4nihwDBuxIdGU2s+AtsO5C2FVJrI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=C/fJecnFX+K1Wr95ftqRLI9EcS4qPNkP7/IVfKs2PdktChi6G+IdKHVCiwzjIqZCTisTWRec7LoSyekzU3XHZzSb0DrlXml9huU8WerbSN0dfoIDUuZ9Q1Lze6pTS9toP1TsBmKJbyLXgkeY9jCH57vrZ+8BNsPRCKmu+lvEotM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (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=KJYKtAgN; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (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="KJYKtAgN" 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=khqLakZnXrmLWajDW0xGtT9CGiA5uggq6975+xLFSmE=; b=KJYKtAgNOpjTYN8pxUCCmMBxeu jYbdhJH6H1VNpJ2mbJgViY0ma6V9hrYPXVWSQgwwkjz3LSz9dq2i02OSkJbejCTVXUV7yZw/3y5nf 3aXCzGnhpkSSwSLWd9wyzUm7x16Ta+pmCMLKwD/eu3vBxt0pevmZNXqnMvadPCDKGPsARPIcf+oLH 857oAYkyONuS+SK8qDedlwq4bnlzGhTkUiOn854UNiqSjU6/mM3ZPbnRmTBurk38aopOM72UYcIiX VTDQ6k2+wzCjPCXOsCaAo2RRgzD6iVQXXH+MtyMRba1+xp+e/c/8wWo16WZiGz3Q+++Omui5e3ckV NbTi+e+g==; Received: from 77-249-17-89.cable.dynamic.v4.ziggo.nl ([77.249.17.89] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tKbQ3-00000003WkK-2ZSo; Mon, 09 Dec 2024 10:55:15 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 8B9FA3003FF; Mon, 9 Dec 2024 11:55:14 +0100 (CET) Date: Mon, 9 Dec 2024 11:55:14 +0100 From: Peter Zijlstra To: Vineeth Remanan Pillai Cc: Joel Fernandes , Ilya Maximets , LKML , Ingo Molnar , Juri Lelli , Vincent Guittot , vineethrp@google.com, shraash@google.com Subject: Re: [v6.12] WARNING: at kernel/sched/deadline.c:1995 enqueue_dl_entity (task blocked for more than 28262 seconds) Message-ID: <20241209105514.GK21636@noisy.programming.kicks-ass.net> References: <571b2045-320d-4ac2-95db-1423d0277613@ovn.org> <20241206151819.GA3949140@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: On Fri, Dec 06, 2024 at 11:57:30AM -0500, Vineeth Remanan Pillai wrote: > I was able to reproduce this WARN_ON couple of days back with > syzkaller. dlserver's dl_se gets enqueued during a update_curr while > the dlserver is stopped. And subsequent dlserver start will cause a > double enqueue. Right, I spotted that hole late last week. There is this thread: https://lore.kernel.org/all/20241209094941.GF21636@noisy.programming.kicks-ass.net/T/#u Where I just added this thunk: @@ -1674,6 +1679,12 @@ void dl_server_start(struct sched_dl_entity *dl_se) void dl_server_stop(struct sched_dl_entity *dl_se) { + if (current->dl_server == dl_se) { + struct rq *rq = rq_of_dl_se(dl_se); + trace_printk("stop fair server %d\n", cpu_of(rq)); + current->dl_server = NULL; + } + if (!dl_se->dl_runtime) return; Which was my attempt at plugging said hole. But since I do not have means of reproduction, I'm not at all sure it is sufficient :/