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 5FD4A15747D; Fri, 4 Oct 2024 13:35:40 +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=1728048942; cv=none; b=th1St6PaFsimcUU+QdxyubqFLcAoXhufL3mj+DT5S9Ws03f6QRMuNPnhqbiVumLECC4eQb74Gz5N8W2qQmbC1iQFZOSLgT5ZM+lzMLQ//55OqmAcDMTjOAQR1SrEhlDPJkM34QsQ+u3IMHZtjtidZLAIkBoNJU1WDPmVft2CbD4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728048942; c=relaxed/simple; bh=Xw3Rk5rZwFBtFSjj2qL9MNa9T6SNgUCIeWAdcMO92y4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nlazr93nvl4gOKolf1Hn/NNB3BHuBuMo1ZY+4E7BeNDHDll9tWvL2raKRkuirXx3o+O8gabYXjU9/0EYVrOM2AVYaDw0zw1dDfOQckhfzT+DL1vvWzZvybR9p2toR3Th1pMA917Czv6KDEQNad/2wIDRGHU1U5gU+3+pWpj26mo= 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=YDkCdg7/; 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="YDkCdg7/" 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=qowZPimobsknCTSPeZx61BV1Jj+jnSrfDL8WG2TTTYE=; b=YDkCdg7/f0SQNMRgFOtmQ7sdRd SX0vVOTXP5dQnm7Ir1BUjaoVsN/eiuOYJ4X4FTOK2U9DiHoq99vSIsQySt6Uyr5Xrdzz+ApqG25kA avywyKZ8Lhotb1C5mQhMwRttaRn1imHKn+Q8x147YEtmQamdNW8rKgMWUaL2COc4UwAgZeACxRWzq WDRhUD4O6BDY2WZVrz4yst7u2v2Pb/Rq11tdb0/NoOSuAZ7kr5oXpAMwZ3/xXfZXZN5ObmpJ1uu13 uaf9W94PK1FXlJTHusJIaA+4vlDmnuBMQQvwQsnVPATKvi5IHHcLIYy/3dZ4CUra4CVYAwsRu/WsU y+Nui4gA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1swiT0-00000003qF0-03z8; Fri, 04 Oct 2024 13:35:34 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id D23C630083E; Fri, 4 Oct 2024 15:35:32 +0200 (CEST) Date: Fri, 4 Oct 2024 15:35:32 +0200 From: Peter Zijlstra To: "Paul E. McKenney" Cc: vschneid@redhat.com, linux-kernel@vger.kernel.org, sfr@canb.auug.org.au, linux-next@vger.kernel.org, kernel-team@meta.com Subject: Re: [BUG almost bisected] Splat in dequeue_rt_stack() and build error Message-ID: <20241004133532.GH33184@noisy.programming.kicks-ass.net> References: <20241003084039.GS5594@noisy.programming.kicks-ass.net> <20241003084743.GC33184@noisy.programming.kicks-ass.net> <20241003092707.GD33184@noisy.programming.kicks-ass.net> <20241003122824.GE33184@noisy.programming.kicks-ass.net> <83d29a0c-dab2-4570-8be0-539b43237724@paulmck-laptop> <20241003142240.GU5594@noisy.programming.kicks-ass.net> <7b14822a-ee98-4e46-9828-1e41b1ce76f3@paulmck-laptop> <20241003185037.GA5594@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-next@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: <20241003185037.GA5594@noisy.programming.kicks-ass.net> On Thu, Oct 03, 2024 at 08:50:37PM +0200, Peter Zijlstra wrote: > On Thu, Oct 03, 2024 at 09:04:30AM -0700, Paul E. McKenney wrote: > > On Thu, Oct 03, 2024 at 04:22:40PM +0200, Peter Zijlstra wrote: > > > On Thu, Oct 03, 2024 at 05:45:47AM -0700, Paul E. McKenney wrote: > > > > > > > I ran 100*TREE03 for 18 hours each, and got 23 instances of *something* > > > > happening (and I need to suppress stalls on the repeat). One of the > > > > earlier bugs happened early, but sadly not this one. > > > > > > Damn, I don't have the amount of CPU hours available you mention in your > > > later email. I'll just go up the rounds to 20 minutes and see if > > > something wants to go bang before I have to shut down the noise > > > pollution for the day... > > > > Indeed, this was one reason I was soliciting debug patches. ;-) > > Sooo... I was contemplating if something like the below might perhaps > help some. It's a bit of a mess (I'll try and clean up if/when it > actually proves to work), but it compiles and survives a hand full of 1m > runs. > > I'll try and give it more runs tomorrow when I can power up the big > machines again -- unless you've already told me it's crap by then :-) I've given it 200*20m and the worst I got was one dl-server double enqueue. I'll go stare at that I suppose.