From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 0021913C9BB for ; Wed, 10 Apr 2024 19:34:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712777677; cv=none; b=L/MSMld5fKRAvosdKEXhRwYlPuiLG0ArUVhpEYn0kC2jU/1tYoTbSHUHvkQnbQdlHCTHlTXWxx+jEiBA4tQ0ULCfB9KK/TM8dBCPf7BqJpN7PMMRjuVuYwratpNK0csitwbpvwueEC6+XlMlP4mNABqJdfAtAKfFA4k46MpbOhI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712777677; c=relaxed/simple; bh=fY6+WvW3hkdWZaAxo0deKXe/8KWqIVNXBr2BIirxmTo=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=R+ahsr+IvqJkrvCmAR8TgwJnrPTgggGmP1g4IhQySXCWfT4a7wHBf3/wRtOH9TUonC2NiaRdkF3zS2b48nMqclPB4GnkdN0NOLh9V+ObFNfDvLC+nQjdU56hF1i5IEAPlVyM17lwyxvr51K4HmVT41mKjxyLosdPyggrhdh9vQI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=HMDN2imC; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=VF7GiSeX; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="HMDN2imC"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="VF7GiSeX" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1712777674; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Zp/EtX3qMN10K3KBzcAg3kdV/12QTlHSX0dqop3x9f4=; b=HMDN2imCIBN/b7ktsutXjXqjRDR7ntAAA/CnE+hm6mQ7/sJYLvqEE0lO3XArMcjBDvKRAl jiUd4PIbqpIjqAtMgcitbHG0IaLWwpxeGBKAo1SvQ/Q0F18FN5THvocPgVleXQRGWwrv1W Vzconq2cnuM3ymru3Nwgz/OgNNsv+VTD8X68fKB4WtpCpyoOER2qd4Clo+EabHdW1x6gwJ QiHJWGRLyIBsv/Z6fj2kEUpp5GjSCL3FrZT+wCxwk6H5Z0gYFTaGoJ6MJvCK/HEp3MzSgL 1TluufqU/8ppM/lHE85jqmdgwTLCj3pnN0Ppv5op2izJlEZ4DAkSj7QToDTClA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1712777674; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Zp/EtX3qMN10K3KBzcAg3kdV/12QTlHSX0dqop3x9f4=; b=VF7GiSeXE+n5qF/XYUxQetLULBfufOdvK8N14QmUpiVo0kAUVsFM29l1FkIntAvtxJmjLL 2+Gn94YJs4hqjxDA== To: Laura Nao Cc: kernel@collabora.com, laura.nao@collabora.com, linux-kernel@vger.kernel.org, regressions@leemhuis.info, regressions@lists.linux.dev, x86@kernel.org Subject: Re: [REGRESSION] mainline boot regression on AMD Stoney Ridge Chromebooks In-Reply-To: <20240410161141.261818-1-laura.nao@collabora.com> References: <878r1l48xn.ffs@tglx> <20240410161141.261818-1-laura.nao@collabora.com> Date: Wed, 10 Apr 2024 21:34:33 +0200 Message-ID: <87il0p2era.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Laura! On Wed, Apr 10 2024 at 18:11, Laura Nao wrote: > On 4/10/24 15:57, Thomas Gleixner wrote: >> I just moved the exit check a bit so we should see the scan info. That >> should tell me what goes south. > > Here's the full kernel log with the latest patch applied: > https://pastebin.com/raw/r2CkP396 Ok. Now I can see it. pr_info("NPP %u\n", tscan.amd_nodes_per_pkg); The output is: <6>[ 0.000000] NPP 3 The original code then reads out 1, which is what's expected on that machine. Now that bogus value '3' is used later in a %= b / 3 as b == 2, the division result is zero, which makes the %= operation crash with a division by zero. As there are no handlers yet, nothing to see. The problem causing the bogus readout sits between my keyboard and my chair. I'll send out the fixes with proper change logs later tonight. Thanks for all your help! tglx