Bug#1117002: 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
- To: Dave Hansen <dave.hansen@intel.com>
- Cc: Salvatore Bonaccorso <carnil@debian.org>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, Dave Hansen <dave.hansen@linux.intel.com>, Laurențiu Păncescu <lpancescu@gmail.com>, x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>, Sohil Mehta <sohil.mehta@intel.com>, "Chang S. Bae" <chang.seok.bae@intel.com>, Andi Kleen <ak@linux.intel.com>, Eric Biggers <ebiggers@google.com>, linux-kernel@vger.kernel.org, 1117002@bugs.debian.org
- Subject: Bug#1117002: 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
- From: Dominik 'Rathann' Mierzejewski <dominik@greysector.net>
- Date: Mon, 1 Dec 2025 21:29:37 +0100
- Message-id: <[🔎] aS36sX1zP8760L7f@amaterasu.greysector.net>
- Reply-to: Dominik 'Rathann' Mierzejewski <dominik@greysector.net>, 1117002@bugs.debian.org
- In-reply-to: <[🔎] d0be2023-1dd4-4465-8153-d0f3f426a217@intel.com>
- References: <aPJNPPFKsPKJWlLn@eldamar.lan> <a7fa4a93-2d80-4c1d-af91-9dad9626ed9f@intel.com> <aShGJfVxuHqRZr1l@amaterasu.greysector.net> <[🔎] d0be2023-1dd4-4465-8153-d0f3f426a217@intel.com> <175938155575.1672.2317462226261584691.reportbug@snowbell.laurentiupancescu.com>
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
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