From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from avasout-ptp-001.plus.net (avasout-ptp-001.plus.net [84.93.230.227]) (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 2BE4A1CA80 for ; Fri, 26 Jul 2024 21:21:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=84.93.230.227 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722028897; cv=none; b=CkdLL9pKwrZrDu9zFutT2ruXugwDyueB+XI/EAjXamkn/cAnfMDLVmv6vVOLSNavKao+9RjMxSLcerzJ4tEX4lkpbpp0npmTVuTtxvdrLF4BkvMA5Z+8og/6fG+K9AmU9OHtlL1Z6AzrwoIlZOsumaeo6Z6Elwdnu0Asg6DA+Vs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722028897; c=relaxed/simple; bh=+fQGq7FP+8GCBDddY8GyNLDMYtE6TTBfTBXaxeMJ8AU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bQc5F/XHaw4e6ogJjKlmmWf0/NiqCMiN8Sn6SWLW1lmMLwBM77ArtNYVLlV+t/OpVo11sDE/Dk0eYDLuc3HD0U/4eNlNZhzOJeuPnt9ITh4iNzq/uLk1TzgVrgrjhxkcvoHI3nog4nM/dkJK6bjGXaU4Gk7oPEIGxpZtlMdzkuQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=durendal.co.uk; spf=none smtp.mailfrom=durendal.co.uk; arc=none smtp.client-ip=84.93.230.227 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=durendal.co.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=durendal.co.uk Received: from localhost ([146.198.41.26]) by smtp with ESMTPA id XSKSsmvFt4PsgXSKUssYcq; Fri, 26 Jul 2024 22:18:25 +0100 X-Clacks-Overhead: "GNU Terry Pratchett" X-CM-Score: 0.00 X-CNFS-Analysis: v=2.4 cv=eeSefKEH c=1 sm=1 tr=0 ts=66a412a1 a=uPaVN7U6Dr8slOeZeejB6w==:117 a=uPaVN7U6Dr8slOeZeejB6w==:17 a=kj9zAlcOel0A:10 a=1A_nFRkuvXKRJ0p9eSIA:9 a=CjuIK1q_8ugA:10 X-AUTH: gnulinux@:2500 Date: Fri, 26 Jul 2024 22:18:19 +0100 From: Rob To: Thomas Gleixner Cc: Christian Heusel , Borislav Petkov , regressions@lists.linux.dev, x86@kernel.org, Joerg Roedel Subject: Re: [REGRESSION][BISECTED] Early boot hangs since f0551af02130 Message-ID: References: <361b2ba5-7fc3-4e9a-af63-adfd4bc20304@heusel.eu> <20240723120246.GBZp-b5nHHT0BWmKMZ@fat_crate.local> <5e08cab0-c6b5-4169-8d42-ddb0ffb4a6c9@heusel.eu> <20240725105029.GAZqIt9aLsIaG7JqN5@fat_crate.local> <12df8b45-6100-4c8b-b82a-a6a75bed2e05@heusel.eu> <87a5i4whoz.ffs@tglx> Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <87a5i4whoz.ffs@tglx> X-CMAE-Envelope: MS4xfN2cOj5j2kaxCiLZJI6nZpfvi60Lq1PmQ+7GbY8VIYKeMkNATxhCKEskr/HQfDeIyEBTzvsGlU2FlavYprjddCnkEUgB9U0r6vcpoFb9IbY0CkGyTSXZ sfcvwm/USJuw+VfHbyZJjKjKmTk3H7KKS3m3761PtlieH2LLXrE2rBWTFdZoQHI6uRqa0dCe57dLag== >So in theory the same problem should happen with a pre 6.9 kernel and >'nr_cpus=4' on the kernel command line. Can you please verify? Confirmed, 6.6.40-2-lts with 'nr_cpus=4' hangs >Another data point to be evaluated is whether booting the unmodified >6.10+ kernel with 'nointremap' instead of 'iommu=off' on the command >line makes the machine boot as well. linux-mainline 6.10-1.1 with 'nointremap' boots >... connect that machine over serial ... Unfortunately I don't have the hardware for this Kind regards, Rob * Thomas Gleixner (tglx@linutronix.de) wrote: >On Fri, Jul 26 2024 at 00:01, Christian Heusel wrote: >> Sorry for causing some confusion on that part and I hope the above >> outputs help with debugging this issue! > >Not really. The issue is completely unclear and nothing makes any sense >here. > >The only difference is the resulting number of possible CPUs. > >[ 0.026516] CPU topo: Allowing 4 present CPUs plus 12 hotplug CPUs > >versus: > >[ 0.025251] CPU topo: Allowing 4 present CPUs plus 0 hotplug CPUs > >which really should not make any difference because the 1300X has only 4 >CPUs. > >So the bisected commit is the messenger for some other problem >presumably in the IOMMU area which is just papered over when there are >12 possible hotplug CPUs enumerated. > >So in theory the same problem should happen with a pre 6.9 kernel and >'nr_cpus=4' on the kernel command line. Can you please verify? > >Another data point to be evaluated is whether booting the unmodified >6.10+ kernel with 'nointremap' instead of 'iommu=off' on the command >line makes the machine boot as well. > >Thanks, > > tglx -- Rob Newcater