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From: Borislav Petkov <bp@alien8.de>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Jue Wang <juew@google.com>, "x86@kernel.org" <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"patches@lists.linux.dev" <patches@lists.linux.dev>
Subject: Re: [PATCH] x86/mce: Add workaround for SKX/CLX/CPX spurious machine checks
Date: Wed, 16 Feb 2022 19:52:58 +0100	[thread overview]
Message-ID: <Yg1ICgHfMYxwHyig@zn.tnic> (raw)
In-Reply-To: <9f402331d25c47b69349c8171bbd49c1@intel.com>

On Wed, Feb 16, 2022 at 06:41:58PM +0000, Luck, Tony wrote:
> > Well, we could try to decode the instructions around rIP when the #MC
> > is raised and see what caused the MCE and perhaps pick apart which insn
> > caused it, is it accessing behind the buffer boundaries, etc.
> 
> Is this a case of "perfect is the enemy of good enough"?

Well, you guys sounded like this happens left and right...

> It is a rare scenario (only a pain point for Jue because Google has
> billions and billions of cores running this code). You need:
>
> 1) An uncorrected error
> 2) That error must be in first cache line of a page
> 3) Kernel must execute page_copy from the page immediately before that page
> 
> 	When all three happen, kernel crashes because we don't
> 	have a recover path from kernel page_copy

You should've lead with that - this is basically one of those "under a
complex set of conditions" things.

Anything against me adding them to the commit message?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2022-02-16 18:53 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-07  4:36 [RFC] x86/mce: Add workaround for SKX/CLX/CPX spurious machine checks Jue Wang
2022-02-07 18:23 ` Luck, Tony
2022-02-07 18:52 ` Borislav Petkov
2022-02-07 19:24   ` Luck, Tony
2022-02-07 20:27     ` Borislav Petkov
2022-02-07 21:07       ` Luck, Tony
2022-02-07 21:20         ` Borislav Petkov
2022-02-07 21:51           ` Luck, Tony
2022-02-08 15:04             ` Jue Wang
2022-02-08 15:09               ` [PATCH] " Jue Wang
2022-02-11 20:08                 ` Jue Wang
2022-02-11 20:18                   ` Borislav Petkov
2022-02-11 20:23                     ` Jue Wang
2022-02-15 18:42                 ` Luck, Tony
2022-02-15 22:08                 ` Borislav Petkov
2022-02-15 22:22                   ` Luck, Tony
2022-02-16 10:28                     ` Borislav Petkov
2022-02-16 15:50                       ` Jue Wang
2022-02-16 18:02                         ` Borislav Petkov
2022-02-16 18:41                           ` Luck, Tony
2022-02-16 18:52                             ` Borislav Petkov [this message]
2022-02-16 18:58                               ` Luck, Tony
2022-02-16 18:59                                 ` Jue Wang
2022-02-16 21:53                                   ` [PATCH] x86/mce: work around an erratum on fast string copy instructions Jue Wang
2022-02-17 16:30                                     ` Borislav Petkov
2022-02-17 16:32                                       ` Borislav Petkov
2022-02-18  1:32                                         ` [PATCH v2] " Jue Wang
2022-02-18 15:07                                           ` Borislav Petkov
2022-02-18 16:03                                             ` Jue Wang
2022-02-18 16:14                                               ` Borislav Petkov
2022-02-18 16:21                                                 ` Jue Wang
2022-02-18 17:16                                                   ` Borislav Petkov
2022-02-18 17:39                                                     ` Jue Wang
     [not found]                                                     ` <CAPcxDJ7=hCz6KRih4OBVv-k8WLcBL4n+VSpeP_zky7Uunq89zg@mail.gmail.com>
2022-02-18 22:05                                                       ` Borislav Petkov
2022-02-18 22:38                                                         ` Luck, Tony
2022-02-18 22:58                                                           ` Borislav Petkov
2022-02-18 17:58                                             ` Luck, Tony
2022-02-19 18:09                                           ` [tip: ras/core] x86/mce: Work " tip-bot2 for Jue Wang
2022-02-16  5:40                   ` [PATCH] x86/mce: Add workaround for SKX/CLX/CPX spurious machine checks Jue Wang
2022-02-16  5:56                     ` [PATCH] x86/mce: work around an erratum on fast string copy instructions Jue Wang
2022-02-16  9:04                       ` David Laight
2022-02-16 15:33                         ` Jue Wang

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