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 2F3E669D2B; Wed, 9 Apr 2025 15:27:14 +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=1744212437; cv=none; b=tbQh3Dfb6CIoK01Po6NwTRp0iQTt+3M4Tff6H/l4BTdYPIrWfMjebxdAp1E7xEtoqenVsZHshgcDUN9wZNT4yHMuGW7ttcAVoONVY0vrL2KWbiR1hY/8I43IGGTjNVj2p6PSsunyx0PHynmk5dRofraxB7xQCk5xzxKF+SreQD8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744212437; c=relaxed/simple; bh=qbv5VX98vIcIPOUSeR4TxxKkhB/UgpxzgMbNDUt70To=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=c0V/suLaxdKs9dSo/DRQCePDMgOLtGf8eYHjknyLccM5j1+46gMHkWqugM1RkYYaRRmvyJlzlmPQhcY7XAO9fT9P9oCWeig0j5IrY49CM+XdpYPFrmrBYqrLcvxOUzQ/4tJcvDeGnMulj9Ck0mFibwGb1/gFkALCw4u/HJDDffI= 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=elsCI4RL; 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="elsCI4RL" 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=wbzNcKaI2Ju+NUurCd+43BqDXaBMvMUrjcEfBIbcm6c=; b=elsCI4RLVTbXJh8m6jf0fPfoZB YWu/Wj9wFWmML48QzkNpHnYgD3fXpjA8vnc54ftkdU+DpTaS6kfXY1sAPZxiLc2Rp62zxKwDWlwP+ edtCHwAy8x3yz6AfLhI64+2FnKYbwiFP+1jeHbBIWBTDq5l0Xil0cv/XLy6GeiwWfYo/LruUln3hk hYOOMxXIkKhcRvxMsoAScZsy0j7FJBERghBSBDrwNGP2KtrnUa6iN8rlmffRYQd+UamqlpsQ/pV5F MRbjWWUc2TeMH+GHIhGA6zbSCZugfXYbBNUiLVkvynJR2mbctO6B9tl7USrPw2JGuDBV/aVcpDPP7 NbpbArNA==; 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 4.98.1 #2 (Red Hat Linux)) id 1u2XKR-00000008dy8-3x7H; Wed, 09 Apr 2025 15:27:04 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 7D8A83003FA; Wed, 9 Apr 2025 17:27:03 +0200 (CEST) Date: Wed, 9 Apr 2025 17:27:03 +0200 From: Peter Zijlstra To: Rik van Riel Cc: Pat Cody , mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, linux-kernel@vger.kernel.org, patcody@meta.com, kernel-team@meta.com, stable@vger.kernel.org, Breno Leitao Subject: Re: [PATCH] sched/fair: Add null pointer check to pick_next_entity() Message-ID: <20250409152703.GL9833@noisy.programming.kicks-ass.net> References: <20250320205310.779888-1-pat@patcody.io> <20250324115613.GD14944@noisy.programming.kicks-ass.net> <9d38c61098b426777c1a748cf1baf8e57c41c334.camel@surriel.com> <20250402180734.GX5880@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: stable@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 Wed, Apr 09, 2025 at 10:29:43AM -0400, Rik van Riel wrote: > On Wed, 2025-04-02 at 20:07 +0200, Peter Zijlstra wrote: > > > > Anyway, seeing how your min_vruntime is weird, let me ask you to try > > the > > below; it removes the old min_vruntime and instead tracks zero > > vruntime > > as the 'current' avg_vruntime. We don't need the monotinicity filter, > > all we really need is something 'near' all the other vruntimes in > > order > > to compute this relative key so we can preserve order across the > > wrap. > > > > This *should* get us near minimal sized keys. If you can still > > reproduce, you should probably add something like that patch I send > > you > > privately earlier, that checks the overflows. > > Our trouble workload still makes the scheduler crash > with this patch. > > I'll go put the debugging patch on our kernel. > > Should I try to get debugging data with this patch > part of the mix, or with the debugging patch just > on top of what's in 6.13 already? Whatever is more convenient I suppose. If you can dump the full tree that would be useful. Typically the se::{vruntime,weight} and cfs_rq::{zero_vruntime,avg_vruntime,avg_load} such that we can do full manual validation of the numbers.