From: Sean Christopherson <seanjc@google.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Chao Gao <chao.gao@intel.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, tglx@linutronix.de, pbonzini@redhat.com,
peterz@infradead.org, rick.p.edgecombe@intel.com,
weijiang.yang@intel.com, john.allen@amd.com, bp@alien8.de,
chang.seok.bae@intel.com, xin3.li@intel.com,
Dave Hansen <dave.hansen@linux.intel.com>,
Eric Biggers <ebiggers@google.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Kees Cook <kees@kernel.org>,
Maxim Levitsky <mlevitsk@redhat.com>,
Mitchell Levy <levymitchell0@gmail.com>,
Nikolay Borisov <nik.borisov@suse.com>,
Oleg Nesterov <oleg@redhat.com>,
Sohil Mehta <sohil.mehta@intel.com>,
Stanislav Spassov <stanspas@amazon.de>,
Vignesh Balasubramanian <vigbalas@amd.com>
Subject: Re: [PATCH v8 0/6] Introduce CET supervisor state support
Date: Fri, 23 May 2025 10:48:55 -0700 [thread overview]
Message-ID: <aDC1B-ngse3HGh-7@google.com> (raw)
In-Reply-To: <f575567b-0d1f-4631-ad48-1ef5aaca1f75@intel.com>
On Fri, May 23, 2025, Dave Hansen wrote:
> On 5/23/25 09:57, Sean Christopherson wrote:
> > Side topic, and *probably* unrelated to this series, I tripped the following
> > WARN when running it through the KVM tests (though I don't think it has anything
> > to do with KVM?). The WARN is the version of xfd_validate_state() that's guarded
> > by CONFIG_X86_DEBUG_FPU=y.
> >
> > WARNING: CPU: 232 PID: 15391 at arch/x86/kernel/fpu/xstate.c:1543 xfd_validate_state+0x65/0x70
>
> Huh, and the two processes getting hit by it:
>
> CPU: 232 UID: 0 PID: 15391 Comm: DefaultEventMan ...
> CPU: 77 UID: 0 PID: 14821 Comm: futex-default-S ...
>
> don't _look_ like KVM test processes.
Yeah, that's why I haven't dug into it, I don't really know where to start, and
I don't even really know what triggered it.
> My guess would be it's some mixture of KVM and a signal handler fighting with
> XFD state.
>
> I take it this is a Sapphire Rapids system?
Emerald Rapids
> Is there anything interesting about the config other than CONFIG_X86_DEBUG_FPU?
The only thing I can think of that's remotely interesting is CONFIG_PROVE_LOCKING=y.
Other than that, it's a pretty vanilla config.
next prev parent reply other threads:[~2025-05-23 17:48 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-22 15:10 [PATCH v8 0/6] Introduce CET supervisor state support Chao Gao
2025-05-22 15:10 ` [PATCH v8 1/6] x86/fpu/xstate: Differentiate default features for host and guest FPUs Chao Gao
2025-05-29 20:59 ` John Allen
2025-05-22 15:10 ` [PATCH v8 2/6] x86/fpu: Initialize guest FPU permissions from guest defaults Chao Gao
2025-05-29 21:14 ` John Allen
2025-05-22 15:10 ` [PATCH v8 3/6] x86/fpu: Initialize guest fpstate and FPU pseudo container " Chao Gao
2025-05-29 21:25 ` John Allen
2025-05-22 15:10 ` [PATCH v8 4/6] x86/fpu: Remove xfd argument from __fpstate_reset() Chao Gao
2025-05-29 21:26 ` John Allen
2025-05-22 15:10 ` [PATCH v8 5/6] x86/fpu/xstate: Introduce "guest-only" supervisor xfeature set Chao Gao
2025-05-30 16:04 ` John Allen
2025-05-22 15:10 ` [PATCH v8 6/6] x86/fpu/xstate: Add CET supervisor xfeature support as a guest-only feature Chao Gao
2025-05-30 16:05 ` John Allen
2025-05-23 16:57 ` [PATCH v8 0/6] Introduce CET supervisor state support Sean Christopherson
2025-05-23 17:12 ` Dave Hansen
2025-05-23 17:48 ` Sean Christopherson [this message]
2025-05-27 11:01 ` Chao Gao
2025-06-02 19:12 ` Chang S. Bae
2025-06-03 6:22 ` Chao Gao
2025-06-03 18:32 ` Chang S. Bae
2025-06-04 0:56 ` Chao Gao
2025-06-04 18:45 ` Dave Hansen
2025-06-16 8:08 ` Chao Gao
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