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 8787633F58C for ; Tue, 21 Apr 2026 20:56:57 +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=1776805019; cv=none; b=BOSOzai0Y1zuX/yKSQ2aOjMfRH3O8ThfeouO8cGTOlnmyiFc8TPqch1Ru3FTN+xbiF8M1UQpRF03WaW+44hsGHM3z1cHF7/ihgzF6a16FHjpLA1/JDyj2rCvt2Up4eTxqt8TxvZtbUWkpVOi+EyhVRGNQjzBoyf2iL8p1qk6grE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776805019; c=relaxed/simple; bh=HQNXdY633oUq2/G6Wa0Ck2ty3NTA2W8JYCXgkQI+FfM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TGPio2pIpACOY1ZaPuK4NowsVp6+TjIzFMnOeAKoTXjFxrl2nd2x5CBvjyFBsXuAnRQ6ERut2sMZU38Y9JUW8vyKRl+J0spvXjZy/rS5hBpcHfTYR5YF45O+MwVgYzhyWbXWRY+vXZoQk1ACo73thUZ6monb45Jl5A5fk6PVBAs= 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=VORS9GG9; 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="VORS9GG9" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=yziRkxzm/jHu5XvBR48lngwQjRBkmDIogI4RwrgqglQ=; b=VORS9GG9jBYojwFqxkmdp2SriT /UZNmaTp2FiCVQ59y3lOGt6by2FFNMZa4YOgjvuA/g0H3B3/JUI6C2DkZ+IPXwnx83ayFUEqnPAAL 086FFSSL12CQwRmOyKu0ZnIXZw0qVqJ4bpti/KZrfcQbYvODDiPjnXimW1YQu8ONhdmaZY9vIepFP hza/huR2LU9e0uxVlShMJi9SoGpDuIS1rHxyPOnexgxB5mom6x5wg+0DKjjAEU55Vb9kqmH9axXIn TM7PZF1T9Qfxvlm7ElLVqFBUeg6zPPRrR10lkQMbDcMvjRfbJ3ubqH0lhL3oyqsjuLQn5ZXB2IMel HY+dpKrA==; Received: from 2001-1c00-8d85-4b00-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:4b00:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1wFI9J-0000000AQ7T-47lb; Tue, 21 Apr 2026 20:56:50 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 0486C300BD2; Tue, 21 Apr 2026 22:56:48 +0200 (CEST) Date: Tue, 21 Apr 2026 22:56:47 +0200 From: Peter Zijlstra To: John Stultz Cc: K Prateek Nayak , "Borah, Chaitanya Kumar" , willy@infradead.org, linux-kernel@vger.kernel.org, "intel-gfx@lists.freedesktop.org" , "intel-xe@lists.freedesktop.org" , "Kurmi, Suresh Kumar" , "Saarinen, Jani" , ravitejax.veesam@intel.com Subject: Re: Regression on linux-next (next-20260324 ) Message-ID: <20260421205647.GL3126523@noisy.programming.kicks-ass.net> References: <20260327164353.GM3739106@noisy.programming.kicks-ass.net> <20260330195037.GW2872@noisy.programming.kicks-ass.net> <20260420130318.GD3102924@noisy.programming.kicks-ass.net> <20260421101521.GO3102624@noisy.programming.kicks-ass.net> <95651a71-1adf-45ba-83eb-5744bc6d4a52@amd.com> <20260421143752.GD1064669@noisy.programming.kicks-ass.net> 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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Tue, Apr 21, 2026 at 10:29:28AM -0700, John Stultz wrote: > On Tue, Apr 21, 2026 at 8:48 AM K Prateek Nayak wrote: > > On 4/21/2026 8:07 PM, Peter Zijlstra wrote: > > >> First hunk orders the first_waiter if we are attaching to the > > >> tail of current first_waiter which would have previously ended > > >> up next to list_head. > > > > > > This is the case in __ww_mutex_add_waiter() where pos == first, right? > > > > > > Argh, I see... yes. Perhaps something like the below though? > > > > Neat! Thank you for cleaning it up. Those, along with the changes in > > ww_mutex.h fix the issue of ww-mutex_test hanging in my case. Feel free > > to include: > > > > Tested-by: K Prateek Nayak > > Same. With Peter's change and K Prateek's ww_mutex.h change it looks > like it's working for me. > > Thank you both! > Tested-by: John Stultz Excellent, I'll write it up tomorrow.