From: Thomas Gleixner <tglx@linutronix.de>
To: Andy Lutomirski <luto@kernel.org>, "Luck\, Tony" <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/5] x86/mce: Fix all mce notifiers to update the mce->handled bitmask
Date: Fri, 14 Feb 2020 01:18:27 +0100 [thread overview]
Message-ID: <87pneiggx8.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <CALCETrVrL1Ps9ubAcKQykxTofn4hbkESBYE9H22Ws5Pis_vG+g@mail.gmail.com>
Andy Lutomirski <luto@kernel.org> writes:
> On Thu, Feb 13, 2020 at 2:19 PM Luck, Tony <tony.luck@intel.com> wrote:
>>
>> On Thu, Feb 13, 2020 at 06:03:08PM +0100, Borislav Petkov wrote:
>> > On Wed, Feb 12, 2020 at 12:46:51PM -0800, Tony Luck wrote:
>> > > If the handler took any action to log or deal with the error, set
>> > > a bit int mce->handled so that the default handler on the end of
>> > > the machine check chain can see what has been done.
>> > >
>> > > [!!! What to do about NOTIFY_STOP ... any handler that returns this
>> > > value short-circuits calling subsequent entries on the chain. In
>> > > some cases this may be the right thing to do ... but it others we
>> > > really want to keep calling other functions on the chain]
>> >
>> > Yes, we can kill that NOTIFY_STOP thing in the mce code since it is
>> > nasty.
>>
>> Well, there are places where we want to keep NOTIFY_STOP.
>
> I very very strongly disagree.
Ack. The unholy mess of cpu hotplug notifiers and the at least 50 bugs
which were unearthed by converting them to a comprehensible and
symmetric state machine have documented the insanity of notifiers
nicely.
>> 1) Default case for CEC. We want it to "hide" the corrected error.
>> That was one of the main goals for CEC. We've discussed cases
>> where CEC shouldn't hide (when internal threshold exceeded and
>> it tries to take a page offline ... probably something related to
>> CMCI storms ... though we didn't really come to any conclusion)
>
> Then put this logic in do_machine_check() or in some sensible place
> that it calls via some ops structure or directly. Don't hide it in
> some incomprehensible, possibly nondeterministic place in a notifier
> chain.
>
>> 2) Errata. Perhaps a vendor/platform specific function at the head
>> of the notify chain that weeds out errors that should never have
>> been reported.
>
> No, do this before the notifier chain please.
Right. The amount of possible handlers is really not huge.
So having a well defined flow of explicit calls including the handling
of magic workarounds in a central place makes tons of sense.
Thanks,
tglx
next prev parent reply other threads:[~2020-02-14 0:18 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-12 20:46 [RFC PATCH 0/5] New way to track mce notifier chain actions Tony Luck
2020-02-12 20:46 ` [PATCH 1/5] x86/mce: Rename "first" function as "early" Tony Luck
2020-02-12 20:46 ` [PATCH 2/5] x86/mce: Convert corrected error collector to use mce notifier Tony Luck
2020-02-12 20:46 ` [PATCH 3/5] x86/mce: Add new "handled" field to "struct mce" Tony Luck
2020-02-13 16:56 ` Borislav Petkov
2020-02-13 22:09 ` Luck, Tony
2020-02-14 8:50 ` Borislav Petkov
2020-02-12 20:46 ` [PATCH 4/5] x86/mce: Fix all mce notifiers to update the mce->handled bitmask Tony Luck
2020-02-13 17:03 ` Borislav Petkov
2020-02-13 22:19 ` Luck, Tony
2020-02-13 22:27 ` Andy Lutomirski
2020-02-13 23:08 ` Luck, Tony
2020-02-14 9:02 ` Borislav Petkov
2020-02-14 0:18 ` Thomas Gleixner [this message]
2020-02-14 8:59 ` Borislav Petkov
2020-02-12 20:46 ` [PATCH 5/5] x86/mce: Change default mce logger to check mce->handled Tony Luck
2020-02-13 17:08 ` Borislav Petkov
2020-02-13 22:27 ` Luck, Tony
2020-02-14 9:05 ` Borislav Petkov
2020-02-12 23:08 ` [RFC PATCH 0/5] New way to track mce notifier chain actions Luck, Tony
2020-02-13 5:52 ` Andy Lutomirski
2020-02-13 6:09 ` Borislav Petkov
2020-02-13 16:05 ` Andy Lutomirski
2020-02-14 22:27 ` [PATCH v2 0/7] " Tony Luck
2020-02-14 22:27 ` [PATCH v2 1/7] x86/mce: Rename "first" function as "early" Tony Luck
2020-04-15 9:49 ` [tip: ras/core] " tip-bot2 for Tony Luck
2020-02-14 22:27 ` [PATCH v2 2/7] x86/mce: Convert corrected error collector to use mce notifier Tony Luck
2020-04-15 9:49 ` [tip: ras/core] x86/mce: Convert the CEC to use the MCE notifier tip-bot2 for Tony Luck
2020-02-14 22:27 ` [PATCH v2 3/7] x86/mce: Add new "kflags" field to "struct mce" Tony Luck
2020-04-15 9:49 ` [tip: ras/core] x86/mce: Add a struct mce.kflags field tip-bot2 for Tony Luck
2020-04-15 18:19 ` Luck, Tony
2020-04-15 18:36 ` Borislav Petkov
2020-04-15 19:58 ` [PATCH] x86/mce: Drop bogus comment about mce.kflags Luck, Tony
2020-04-17 9:21 ` [tip: ras/core] " tip-bot2 for Tony Luck
2020-04-20 8:06 ` [tip: ras/core] x86/mce: Add a struct mce.kflags field Christoph Hellwig
2020-04-20 8:42 ` Borislav Petkov
2020-02-14 22:27 ` [PATCH v2 4/7] x86/mce: Fix all mce notifiers to update the mce->kflags bitmask Tony Luck
2020-04-07 8:21 ` Borislav Petkov
2020-04-15 9:49 ` [tip: ras/core] " tip-bot2 for Tony Luck
2020-02-14 22:27 ` [PATCH v2 5/7] x86/mce: Change default mce logger to check mce->kflags Tony Luck
2020-04-07 11:10 ` Borislav Petkov
2020-04-07 16:43 ` Luck, Tony
2020-04-07 19:37 ` Borislav Petkov
2020-04-07 19:44 ` Luck, Tony
2020-04-15 9:49 ` [tip: ras/core] x86/mce: Change default MCE " tip-bot2 for Tony Luck
2020-02-14 22:27 ` [PATCH v2 6/7] x86/mce: Add mce=print_all option Tony Luck
2020-04-15 9:49 ` [tip: ras/core] " tip-bot2 for Tony Luck
2020-02-14 22:27 ` [PATCH v2 7/7] x86/mce: Drop the EDAC report status checks Tony Luck
2020-04-15 9:49 ` [tip: ras/core] EDAC: " tip-bot2 for Tony Luck
2020-04-07 16:34 ` [PATCH 0/9 v3] New way to track mce notifier chain actions Borislav Petkov
2020-04-07 16:34 ` [PATCH 1/9] x86/mce/amd, edac: Remove report_gart_errors Borislav Petkov
2020-04-15 9:49 ` [tip: ras/core] " tip-bot2 for Borislav Petkov
2020-04-07 16:34 ` [PATCH 2/9] x86/mce: Rename "first" function as "early" Borislav Petkov
2020-04-07 16:34 ` [PATCH 3/9] x86/mce: Convert the CEC to use the MCE notifier Borislav Petkov
2020-04-07 16:34 ` [PATCH 4/9] x86/mce: Add a struct mce.kflags field Borislav Petkov
2020-04-07 16:34 ` [PATCH 5/9] x86/mce: Fix all mce notifiers to update the mce->kflags bitmask Borislav Petkov
2020-04-07 16:34 ` [PATCH 6/9] x86/mce: Change default MCE logger to check mce->kflags Borislav Petkov
2020-04-07 16:34 ` [PATCH 7/9] x86/mce: Add mce=print_all option Borislav Petkov
2020-04-07 16:34 ` [PATCH 8/9] EDAC: Drop the EDAC report status checks Borislav Petkov
2020-04-07 16:34 ` [PATCH 9/9] x86/mce: Fixup exception only for the correct MCEs Borislav Petkov
2020-04-15 9:49 ` [tip: ras/core] " tip-bot2 for Borislav Petkov
2020-04-07 19:53 ` [PATCH 0/9 v3] New way to track mce notifier chain actions Luck, Tony
2020-04-07 19:56 ` Borislav Petkov
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