linux-kernel - Re: [RFC] #MC mess

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Message-ID: <20200218200900.GS14449@zn.tnic>
Date:   Tue, 18 Feb 2020 21:09:00 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     "Luck, Tony" <tony.luck@...el.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Andy Lutomirski <luto@...nel.org>, x86-ml <x86@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [RFC] #MC mess

On Tue, Feb 18, 2020 at 09:02:00PM +0100, Peter Zijlstra wrote:
> Then please rewrite the #MC entry code to deal with nested exceptions
> unmasking the MCE, very similr to NMI.
> 
> The moment you allow tracing, jump_labels or anything else you can
> expect #PF, #BP and probably #DB while inside #MC, those will then IRET
> and re-enable the #MC.

Yeah, I'd like to keep it simple and reenable all the crap we disabled
only on exit from the handler.

Dunno if we care about losing tracing samples when an MCE happened...

> The current situation is completely and utterly buggered.

Lovely. ;-(

-- 
Regards/Gruss,
    Boris.

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