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From: Barret Rhoden <brho@google.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	"Rik van Riel\"" <riel@surriel.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>
Subject: AVX register corruption from signal delivery
Date: Tue, 26 Nov 2019 14:49:55 -0500
Message-ID: <c87e93c3-5f30-f242-74b7-6c7ccc91158a@google.com> (raw)

Hi -

The Go Team found a bug[1] where the AVX registers can get corrupted 
during signal delivery.  They were able to bisect it to commits related 
to the "x86: load FPU registers on return to userland" patchset[2].

The bug requires the kernel to be built with GCC 9 to trigger.  In 
particular, arch/x86/kernel/fpu/signal.c needs to be built with GCC 9.

Thanks,

Barret

[1] https://bugzilla.kernel.org/show_bug.cgi?id=205663
[2] 
https://lore.kernel.org/kvm/20190403164156.19645-1-bigeasy@linutronix.de/


             reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-26 19:49 Barret Rhoden [this message]
2019-11-26 20:20 ` Sebastian Andrzej Siewior
2019-11-26 21:23   ` Barret Rhoden
2019-11-26 22:13     ` Borislav Petkov
2019-11-26 22:30       ` Andy Lutomirski
2019-11-26 23:00         ` Borislav Petkov
2019-11-27 12:42     ` [PATCH] x86/fpu: Don't cache access to fpu_fpregs_owner_ctx Sebastian Andrzej Siewior
2019-11-27 14:07       ` Borislav Petkov
2019-11-27 18:42         ` Barret Rhoden
2019-11-28  8:53           ` [PATCH v2] " Sebastian Andrzej Siewior
2019-11-28  9:22             ` [tip: x86/urgent] " tip-bot2 for Sebastian Andrzej Siewior
2019-11-29 16:57             ` [PATCH v2] " David Laight
2019-11-29 17:08               ` 'Sebastian Andrzej Siewior'
2019-11-27 15:46       ` [PATCH] " Rik van Riel

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