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From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: Andrei Vagin <avagin@google.com>,
	Thomas Gleixner <tglx@kernel.org>,
	"Ingo Molnar" <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>
Cc: <linux-kernel@vger.kernel.org>, <criu@lists.linux.dev>,
	Dave Hansen <dave.hansen@linux.intel.com>, <x86@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 04/10] x86/fpu: Document reasoning of FX-only fallback
Date: Tue, 30 Jun 2026 12:23:46 -0700	[thread overview]
Message-ID: <cc65271d-f582-420e-b8cc-86776d206cd7@intel.com> (raw)
In-Reply-To: <20260615193716.1843340-5-avagin@google.com>

On 6/15/2026 12:37 PM, Andrei Vagin wrote:
> 
> This fallback is dangerous as it can trigger silent corruptions of
> user-space state by resetting extended registers if the process was
> using them but the frame metadata was malformed.
> 
> XSAVE was introduced 15 years ago, we may need to consider removing this
> fallback entirely or introducing a sysctl to enable/disable it.

This reads more like a separate problem statement. I don't see any 
follow-up implementing either option here.

Without additional context, it isn't entirely clear to me why this 
should be in this changelog at least.

Thanks,
Chang

  parent reply	other threads:[~2026-06-30 19:23 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-15 19:37 [PATCH v3 0/10] x86/fpu: Restore and reinforce signal frame portability Andrei Vagin
2026-06-15 19:37 ` [PATCH 01/10] x86/fpu: Document " Andrei Vagin
2026-06-26 13:51   ` Alexander Mikhalitsyn
2026-06-30 19:23   ` Chang S. Bae
2026-06-15 19:37 ` [PATCH 02/10] x86/fpu: Clean up and rename variables in signal frame handling Andrei Vagin
2026-06-26 17:05   ` Alexander Mikhalitsyn
2026-06-15 19:37 ` [PATCH 03/10] x86/fpu: Split __fpu_restore_sig to extract compat path Andrei Vagin
2026-06-26 17:20   ` Alexander Mikhalitsyn
2026-06-15 19:37 ` [PATCH 04/10] x86/fpu: Document reasoning of FX-only fallback Andrei Vagin
2026-06-26 14:22   ` Alexander Mikhalitsyn
2026-06-30 19:23   ` Chang S. Bae [this message]
2026-06-15 19:37 ` [PATCH 05/10] x86/fpu: Fix potential underflow in xstate_calculate_size() Andrei Vagin
2026-06-26 14:32   ` Alexander Mikhalitsyn
2026-06-30 19:23   ` Chang S. Bae
2026-06-15 19:37 ` [PATCH 06/10] selftests/x86: Add a test for signal frame FPU portability Andrei Vagin
2026-06-26 14:39   ` Alexander Mikhalitsyn
2026-06-15 19:37 ` [PATCH 07/10] x86/fpu: Pre-fault only required size of xstate buffer Andrei Vagin
2026-06-26 17:28   ` Alexander Mikhalitsyn
2026-06-15 19:37 ` [PATCH 08/10] selftests/x86: Add a sigframe insufficient xstate_size test Andrei Vagin
2026-06-26 15:02   ` Alexander Mikhalitsyn
2026-06-15 19:37 ` [PATCH 09/10] x86/fpu: Allow restoring signal frames with larger xstate_size Andrei Vagin
2026-06-26 17:32   ` Alexander Mikhalitsyn
2026-06-30 19:23   ` Chang S. Bae
2026-07-01  0:48     ` Andrei Vagin
2026-07-06 17:08       ` Chang S. Bae
2026-07-07 20:27         ` Andrei Vagin
2026-07-09 21:14           ` Chang S. Bae
2026-07-10 22:24             ` Chang S. Bae
2026-06-15 19:37 ` [PATCH 10/10] selftests/x86: Check restoring FPU state " Andrei Vagin
2026-06-26 15:12   ` Alexander Mikhalitsyn

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