From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from arashi.greysector.net (arashi.greysector.net [51.68.141.79]) (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 4B12936D50A for ; Mon, 1 Dec 2025 20:29:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=51.68.141.79 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764620991; cv=none; b=hGtECn4d6RdAInj4I1SHuYoIax3cB6NQ8TRGoO+af5fq0QuvOsp9W2QEHVNZEafQvEQQ9Myhw1Wz9veLJz+rIX2M5JhRo3SJt8VdxKC2V207FAhf/Ra8PzhFJKzG8VsqKcHww44adPPb1E2CbAXGwBANEJe3etEW+K/OvjyH9Eg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764620991; c=relaxed/simple; bh=xJS4UQfNg5hwAZm13f0L1mBtk8a0RGpEQsUVTavSrNQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CEXqvB1I3Anya3VZLSdSijHk//JgtDThvSMiNSlMKYD2hO3EDNddcmaItsXg4MNgvaJ1kHJ0dFncC1xCqnEoWX+/3rMkSFAf1BfwaH7qX6Y0ErU5PlN2SlKPDaZzlw5Gr4ID8l/dqoNuuD4wN+HP+zAc8wig2yqutATY0ixidHE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=greysector.net; spf=pass smtp.mailfrom=greysector.net; dkim=pass (1024-bit key) header.d=greysector.net header.i=@greysector.net header.b=SyJbEkdk; arc=none smtp.client-ip=51.68.141.79 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=greysector.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=greysector.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=greysector.net header.i=@greysector.net header.b="SyJbEkdk" Received: from amaterasu.greysector.net (unknown [212.180.189.198]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by arashi.greysector.net (Postfix) with ESMTPSA id C49A54CB2; Mon, 01 Dec 2025 21:29:38 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 arashi.greysector.net C49A54CB2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=greysector.net; s=default; t=1764620979; bh=ViEZyqUzspLGkVRSkIHvI+xnb9E7B2dr3JnOxHhi2zk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SyJbEkdkENrmwV4TsiYzT/2ORTPe+fMMbB37FTQWpzxKxTznMEUo2L2D+5w8fSt4U IM607WKr4CYRx+Cob+0Kuys1OYDYgB7jIiWEeR8+tuqA3NREREJKEVCkFATCg/eMaj /G14miI3Urw21k4Nb1BKxyg6KZ/VSzQ6dtHxMW0Q= Date: Mon, 1 Dec 2025 21:29:37 +0100 From: Dominik 'Rathann' Mierzejewski To: Dave Hansen Cc: Salvatore Bonaccorso , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , =?utf-8?Q?Lauren=C8=9Biu_P=C4=83ncescu?= , x86@kernel.org, "H. Peter Anvin" , Sohil Mehta , "Chang S. Bae" , Andi Kleen , Eric Biggers , linux-kernel@vger.kernel.org, 1117002@bugs.debian.org Subject: Re: WARNING: CPU: 1 PID: 0 at arch/x86/kernel/cpu/cpuid-deps.c:123 do_clear_cpu_cap+0xdc/0x130 on Intel(R) Atom(TM) CPU N450 system Message-ID: References: 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=us-ascii Content-Disposition: inline In-Reply-To: On Monday, 01 December 2025 at 18:54, Dave Hansen wrote: > On 11/27/25 04:37, Dominik 'Rathann' Mierzejewski wrote: > >> Could you boot the system on a known good kernel and run this, please? > >> > >> rdmsr -a 0x000001a0 > >> > >> That'll dump out MSR_IA32_MISC_ENABLE on all the CPUs. > > # rdmsr -a 0x000001a0 > > 60840488 > > 60840488 > > 60840488 > > 60840489 > > I don't think there's any other way to read this than: the BIOS is buggy > and mis-programmed this MSR on one of the CPUs. We can shut the warning > up, of course. But it _is_ a quite valid warning. I appreciate the explanation. Buggy BIOSes are a sad fact of life. Can I fix that with the following? wrmsr -p 3 0x000001a0 60840488 Would that change anything? > I'm just not sure how much code we want to add to the kernel to silence > a warning on 15-year-old CPUs with buggy BIOSes. Probably not worth any effort, then. > Are there any ill effects other than the warning splat? Kernel becomes tainted, which may lead to bug reports of other valid issues get rejected. I guess that's my main concern. Regards, Dominik -- Fedora https://fedoraproject.org Deep in the human unconscious is a pervasive need for a logical universe that makes sense. But the real universe is always one step beyond logic. -- from "The Sayings of Muad'Dib" by the Princess Irulan